Honors Biology 1st Semester Exam Study Guide

3–2 Energy Flow

Honors Biology

1st Semester Exam Study Guide
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Copyright Pearson Prentice Hall

3–2 Energy Flow Feeding Relationships

Trophic Levels

Each step in a food chain or food web is called a
trophic level.
Sun < Primary Producer < Primary Consumer <
Secondary Consumer < Tertiary Consumer <
Quatenary Consumer
Each consumer depends on the trophic level below
it for energy.

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3–2 Energy Flow Ecological Pyramids

How efficient is the transfer of energy among
organisms in an ecosystem?

Only about 10 percent of the energy available within
one trophic level is transferred to organisms at the
next trophic level.

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0.1% Third-level
Energy Pyramid: consumers
Shows the relative 1% Second-level
amount of energy consumers
available at each
trophic level. 10% First-level
consumers
Only part of the
energy that is stored
in one trophic level is
passed on to the next
level. 100% Producers

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Biomass Pyramid:
50 grams of
Represents the amount of living human tissue
organic matter at each trophic
level. Typically, the greatest
biomass is at the base of the 500 grams of
pyramid. chicken

5000 grams
of grass

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Pyramid of
Numbers:
Shows the relative number
of individual organisms at
each trophic level.

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Food Chains

A food chain is a series of steps in which
organisms transfer energy by eating and being
eaten.

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In some marine food chains, the producers are
microscopic algae and the top carnivore is four steps
removed from the producer.

Small Fish
Zooplankton
Squid
Algae Shark

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Food Webs

Ecologists describe a feeding relationship in an
ecosystem that forms a network of complex
interactions as a food web.
A food web links all the food chains in an
ecosystem together.

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This food web
shows some of
the feeding
relationships in a
salt-marsh
community.

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3–2 Energy Flow Producers

Autotrophs
Only plants, some algae, and certain bacteria can
capture energy from sunlight or chemicals and use
that energy to produce food.
These organisms are called autotrophs.
They harness energy through:
photosynthesis and chemosynthesis
Because they make their own food, autotrophs are
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3–2 Energy Flow Consumers

Heterotrophs
Many organisms cannot harness energy directly
from the physical environment.
Organisms that rely on other organisms for their
energy and food supply are called heterotrophs.
Heterotrophs are also called consumers.

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3–2 Energy Flow Consumers

There are many different types of heterotrophs.

•Herbivores eat plants. (cows, rabbits)
•Carnivores eat animals. (snakes, dogs, owls)
•Omnivores eat both plants and animals. (humans)
•Detritivores feed on plant and animal remains and
other dead matter. (snails, crabs, earthworms)
•Decomposers break down organic matter.
(bacteria, fungi)
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3–2 Energy Flow Nutrient Cycles

Nutrient Cycles
All the chemical substances that an organism needs
to sustain life are its nutrients.

Every living organism needs nutrients to build
tissues and carry out essential life functions.

Similar to water, nutrients are passed between
organisms and the environment through
biogeochemical cycles.

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The Carbon Cycle
Carbon is a key ingredient of living tissue.
Biological processes, such as photosynthesis,
respiration, and decomposition, take up and
release carbon and oxygen.
Geochemical processes, such as erosion and
volcanic activity, release carbon dioxide to the
atmosphere and oceans.

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CO2 in
Atmosphere

Photosynthesis Volcanic
activity

feeding Respiration

Erosion
Human
Decomposition activity Respiration
CO2 in Ocean
Uplift
Deposition
Photosynthesis
feeding

Fossil fuel
Deposition
Carbonate
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The Nitrogen Cycle

All organisms require nitrogen to make proteins.
Although nitrogen gas is the most abundant form of
nitrogen on Earth, only certain types of bacteria can use
this form directly.
Such bacteria live in the soil and on the roots of plants
called legumes. They convert nitrogen gas into ammonia in
a process known as nitrogen fixation.

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N2 in
Atmosphere
Synthetic fertilizer
Atmospheric
manufacturer
Decomposition nitrogen fixation

Uptake by
Reuse by producers
Uptake by consumers Reuse by
producers consumers

Decomposition Decomposition
Bacterial excretion
excretion
nitrogen fixation NO3 and
NO2
NH3

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Other soil bacteria convert nitrates into nitrogen gas
in a process called denitrification.
This process releases nitrogen into the atmosphere
once again.

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The Phosphorus Cycle

Phosphorus is essential to organisms because it
helps forms important molecules like DNA and
RNA.
Most phosphorus exists in the form of inorganic
phosphate. Inorganic phosphate is released into
the soil and water as sediments wear down.

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Organic phosphate
moves through the
food web and to the
rest of the ecosystem. Organisms

Land

Ocean

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3–2 Energy Flow The Major Biomes

Biomes are defined by a unique set of abiotic
factors—particularly climate—and a
characteristic assemblage of plants and
animals.

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60°N

30°N

0° Equator

30°S

60°S

Tropical rain forest Temperate grassland Temperate forest

Tropical dry forest Desert Northwestern
coniferous forest
Tropical savanna Temperate woodland Boreal forest
and shrubland (Taiga)
Tundra Mountains and Slide
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Tropical Rain Forest

Tropical rain forests are home to more species
than all other biomes combined.
The tops of tall trees, extending from 50 to 80
meters above the forest floor, form a dense
covering called a canopy.

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In the shade below the canopy, a second layer of
shorter trees and vines forms an understory.
Organic matter that falls to the forest floor quickly
decomposes, and the nutrients are recycled.

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Abiotic factors: hot and wet year-round; thin,
nutrient-poor soils
Dominant plants: broad-leaved evergreen trees;
ferns; large woody vines and climbing plants

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Dominant wildlife: sloths, capybaras, jaguars,
anteaters, monkeys, toucans, parrots, butterflies,
beetles, piranhas, caymans, boa constrictors, and
anacondas.
Geographic distribution: parts of South and
Central America, Southeast Asia, parts of Africa,
southern India, and northeastern Australia

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Tropical Dry Forest

Tropical dry forests grow in places where rainfall is
highly seasonal rather than year-round.
During the dry season, nearly all the trees drop
their leaves to conserve water.
A tree that sheds its leaves during a particular
season each year is called deciduous.

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Abiotic factors: generally warm year-round;
alternating wet and dry seasons; rich soils subject to
erosion
Dominant plants: tall, deciduous trees; drought-
tolerant plants; aloes and other succulents

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Dominant wildlife: tigers, monkeys, elephants,
Indian rhinoceroses, hog deer, great pied hornbills,
pied harriers, spot-billed pelicans, termites, snakes
and monitor lizards
Geographic distribution: parts of Africa, South and
Central America, Mexico, India, Australia, and
tropical islands

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Tropical Savanna

Tropical savannas, or grasslands, receive more
rainfall than deserts but less than tropical dry
forests.
They are covered with grasses.
Compact soils, fairly frequent fires, and the action
of large animals prevent them from becoming dry
forest.

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Abiotic factors: warm temperatures; seasonal
rainfall; compact soil; frequent fires set by lightning
Dominant plants: tall, perennial grasses; drought-
tolerant and fire-resistant trees or shrubs

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Dominant wildlife: lions, leopards, cheetahs,
hyenas, jackals, aardvarks, elephants, giraffes,
antelopes, zebras, baboons, eagles, ostriches,
weaver birds, and storks
Geographic distribution: large parts of eastern
Africa, southern Brazil, and northern Australia

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Desert

All deserts are dry, defined as having annual
precipitation of less than 25 centimeters.
Deserts vary greatly, some undergoing extreme
temperature changes during the course of a day.
The organisms in this biome can tolerate extreme
conditions.

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Abiotic factors: low precipitation; variable
temperatures; soils rich in minerals but poor in
organic material
Dominant plants: cacti and other succulents; plants
with short growth cycles

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Dominant wildlife: mountain lions, gray foxes,
bobcats, mule deer, pronghorn antelopes, desert
bighorn sheep, kangaroo rats, bats, owls, hawks,
roadrunners, ants, beetles, butterflies, flies, wasps,
tortoises, rattlesnakes, and lizards
Geographic distribution: Africa, Asia, the Middle
East, United States, Mexico, South America, and
Australia

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Temperate Grassland

Temperate grasslands are characterized by a rich
mix of grasses and underlaid by fertile soils.
Periodic fires and heavy grazing by large
herbivores maintain the characteristic plant
community.

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Abiotic factors: warm to hot summers; cold winters;
moderate, seasonal precipitation; fertile soils;
occasional fires
Dominant plants: lush, perennial grasses and
herbs; most are resistant to drought, fire, and cold

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Dominant wildlife: coyotes, badgers, pronghorn
antelopes, rabbits, prairie dogs, introduced cattle,
hawks, owls, bobwhites, prairie chickens, mountain
plovers, snakes, ants and grasshoppers
Geographic distribution: central Asia, North
America, Australia, central Europe, and upland
plateaus of South America

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Temperate Woodland and Shrubland

This biome is characterized by a semiarid climate
and mix of shrub communities and open
woodlands.
Large areas of grasses and wildflowers are
interspersed with oak trees.

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Communities that are dominated by shrubs are also
known as chaparral.
The growth of dense, low plants that contain
flammable oils makes fires a constant threat.

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Abiotic factors: hot, dry summers; cool, moist
winters; thin, nutrient-poor soils; periodic fires
Dominant plants: woody evergreen shrubs; herbs
that grow during winter and die in summer

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Dominant wildlife: coyotes, foxes, bobcats,
mountain lions, black-tailed deer, rabbits, squirrels,
hawks, California quails, warblers, lizards, snakes,
and butterflies
Geographic distribution: western coasts of North
and South America, areas around the
Mediterranean Sea, South Africa, and Australia

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Temperate Forest

Temperate forests contain a mixture of deciduous
and coniferous trees.
Coniferous trees, or conifers, produce seed-
bearing cones and most have leaves shaped like
needles.
These forests have cold winters that halt plant
growth for several months.

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In autumn, the deciduous trees shed their leaves.
Soils of temperate forests are often rich in humus, a
material formed from decaying leaves and other
organic matter that makes soil fertile.

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Abiotic factors: cold to moderate winters; warm
summers; year-round precipitation; fertile soils
Dominant plants: broadleaf deciduous trees; some
conifers; flowering shrubs; herbs; a ground layer of
mosses and ferns

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Dominant wildlife: Deer, black bears, bobcats,
squirrels, raccoons, skunks, numerous songbirds,
turkeys
Geographic distribution: eastern United States;
southeastern Canada; most of Europe; and parts of
Japan, China, and Australia

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Northwestern Coniferous Forest

Mild, moist air from the Pacific Ocean provides
abundant rainfall to this biome.
The forest is made up of a variety of trees,
including giant redwoods, spruce, fir, hemlock, and
dogwood.
Because of its lush vegetation, the northwestern
coniferous forest is sometimes called a ―temperate
rain forest.‖
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Abiotic factors: mild temperatures; abundant
precipitation during fall, winter, and spring; relatively
cool, dry summer; rocky, acidic soils
Dominant plants: Douglas fir, Sitka spruce,
western hemlock, redwood

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Dominant wildlife: bears, elk, deer, beavers, owls,
bobcats, and members of the weasel family
Geographic distribution: Pacific coast of
northwestern United States and Canada, from
northern California to Alaska

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Boreal Forest

Dense evergreen forests of coniferous trees are
found along the northern edge of the temperate
zone.
These forests are called boreal forests, or taiga.

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Winters are bitterly cold.
Summers are mild and long enough to allow the
ground to thaw.
Boreal forests occur mostly in the Northern
Hemisphere.

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Abiotic factors: long, cold winters; short, mild
summers; moderate precipitation; high humidity;
acidic, nutrient-poor soils
Dominant plants: needleleaf coniferous trees;
some broadleaf deciduous trees; small, berry-
bearing shrubs

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Dominant wildlife: lynxes, timber wolves, members
of the weasel family, small herbivorous mammals,
moose, beavers, songbirds, and migratory birds
Geographic distribution: North America, Asia, and
northern Europe

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Tundra

The tundra is characterized by permafrost, a layer
of permanently frozen subsoil.
During the short, cool summer, the ground thaws
to a depth of a few centimeters and becomes
soggy and wet. In winter, the topsoil freezes again.
Cold temperaturs, high winds, the short growing
season, and humus-poor soils also limit plant
height.
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Abiotic factors: strong winds; low precipitation;
short and soggy summers; long, cold, and dark
winters; poorly developed soils; permafrost
Dominant plants: ground-hugging plants such as
mosses, lichens, sedges, and short grasses

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Dominant wildlife: birds, mammals that can
withstand the harsh conditions, migratory waterfowl,
shore birds, musk ox, Arctic foxes, caribou,
lemmings and other small rodents
Geographic distribution: northern North America,
Asia, and Europe

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3–2 Energy Flow Levels of Organization

Biosphere

Biome

Ecosystem

Community

Population

Individual
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A species is a group of organisms so similar to one
another that they can breed and produce fertile
offspring.
Populations are groups of individuals that belong
to the same species and live in the same area.
Communities are assemblages of different
populations that live together in a defined area.

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An ecosystem is a collection of all the organisms
that live in a particular place, together with their
nonliving, or physical, environment.
A biome is a group of ecosystems that have the
same climate and similar dominant communities.
The highest level of organization that ecologists
study is the entire biosphere itself.

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3–2 Energy Flow Community Interactions

Competition

Competition occurs when organisms of the same
or different species attempt to use an ecological
resource in the same place at the same time.

A resource is any necessity of life, such as water,
nutrients, light, food, or space.

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Direct competition in nature often results in a winner
and a loser—with the losing organism failing to
survive.
The competitive exclusion principle states that no
two species can occupy the same niche in the same
habitat at the same time.

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The distribution of these warblers avoids direct
competition, because each species feeds in a
different part of the tree.
18
Feeding height (m)

12
Cape May Warbler

6 Bay-Breasted
Warbler

Yellow-Rumped Warbler
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Predation

An interaction in which one organism captures and
feeds on another organism is called predation.
The organism that does the killing and eating is
called the predator, and the food organism is the
prey.

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Symbiosis

Any relationship in which two species live closely
together is called symbiosis.
Symbiotic relationships include:
• mutualism
• commensalism
• parasitism

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Mutualism: both species benefit from the
relationship.
Commensalism: one member of the association
benefits and the other is neither helped nor
harmed.
Parasitism: one organism lives on or inside
another organism and harms it.

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3–2 Energy Flow Exponential Growth

Exponential Growth
Under ideal conditions with unlimited resources,
a population will grow exponentially.
Exponential growth occurs when the individuals in
a population reproduce at a constant rate.
The population becomes larger and larger until it
approaches an infinitely large size.

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3–2 Energy Flow Exponential Growth

Exponential Growth

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3–2 Energy Flow Logistic Growth

Logistic Growth
As resources become less available, the growth
of a population slows or stops.

Logistic growth occurs when a population's growth
slows or stops following a period of exponential
growth.

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3–2 Energy Flow Logistic Growth

Logistic growth is characterized by an S-
shaped curve.

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3–2 Energy Flow Density-Dependent Factors

Density-Dependent Factors
A limiting factor that depends on population size is
called a density-dependent limiting factor.

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Density-dependent limiting factors include:
• competition
• predation
• parasitism
• disease

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Density-dependent factors operate only when the
population density reaches a certain level. These
factors operate most strongly when a population is
large and dense.
They do not affect small, scattered populations as
greatly.

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3–2 Energy Flow Density-Independent Factors

Density-Independent Factors
Density-independent limiting factors affect all
populations in similar ways, regardless of the
population size.

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3–2 Energy Flow Density-Independent Factors

Examples of density-independent limiting factors
include:
• unusual weather
• natural disasters
• seasonal cycles
• certain human activities—such as damming
rivers and clear-cutting forests

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3–2 Energy Flow Designing an Experiment

Designing an Experiment
The process of testing a hypothesis includes:
• Asking a question
• Forming a hypothesis
• Setting up a controlled experiment
• Recording and analyzing results
• Drawing a conclusion
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Asking a Question

Many years ago, people wanted to know how living
things came into existence. They asked:
How do organisms come into being?

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Forming a Hypothesis

One early hypothesis was spontaneous
generation.

For example, most people thought that maggots
spontaneously appeared on meat.
In 1668, Redi proposed a different hypothesis: that
maggots came from eggs that flies laid on meat.

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Setting Up a Controlled Experiment

manipulated variable

responding variable

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Redi’s Experiment

Uncovered jars Covered jars
Controlled Variables:
jars, type of meat,
Location, temperature,
time

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Redi’s Experiment

Manipulated Variable: Several
Gauze covering that keeps days pass.
flies away from meat

Responding Variable:
whether maggots appear Maggots appear. No maggots appear.

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Drawing a Conclusion

Scientists use the data from an experiment to
evaluate a hypothesis and draw a valid conclusion.

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Experimental Design
Quantitative vs. Qualitative
Quantitative: measured by appearance, by observations;
cannot be measured by numbers
Qualitative: measured by numbers
Independent vs. Dependent
Independent: variable you get to manipulate (usually graphed
on x-axis)
Dependent: variable you don’t get to manipulate that changes
based on the independent variable (usually graphed on y-axis)
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Hypothesis vs. Theory vs. Law
Hypothesis: possible explanation for a set of
observations or possible answer to a scientific
question
Theory: well-tested explanation that unifies a broad
range of observations
Law: concise verbal or mathematical statement of a
relation that expresses a fundamental principle of
science

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3–2 Energy Flow Atoms

Atoms
The study of chemistry begins with the basic unit of
matter, the atom.

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Placed side by side, 100 million atoms would make a
row only about 1 centimeter long.
Atoms contain subatomic particles that are even
smaller.

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The subatomic particles that make up atoms are

•Nucleus
Neutron: neutral (mass: 1)
Proton: positive (mass: 1)
•Outer Shell
Electron: negative (mass: 1/1800)

# protons = # electrons
# protons = atomic #
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The subatomic
particles in a helium
atom.

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3–2 Energy Flow Elements and Isotopes

Elements and Isotopes
A chemical element is a pure substance that
consists entirely of one type of atom.

• C stands for carbon.
• Na stands for sodium.

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The number of protons in an atom of an element is
the element's atomic number.

Commonly found in living organisms:

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Isotopes

Atoms of the same element that differ in the
number of neutrons they contain are known as
isotopes.

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Because they have the same number of
electrons, all isotopes of an element have the
same chemical properties.

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Isotopes of Carbon

6 electrons
6 protons
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Radioactive Isotopes

Some isotopes are radioactive, meaning that their
nuclei are unstable and break down at a constant
rate over time

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Radioactive isotopes can be used:
•to determine the ages of rocks and fossils.
•to treat cancer.
•to kill bacteria that cause food to spoil.
•as labels or ―tracers‖ to follow the movement of
substances within an organism.

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3–2 Energy Flow The Water Molecule

A water molecule is polar because there is an
uneven distribution of electrons between the
oxygen and hydrogen atoms.

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Water
Molecule

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Hydrogen Bonds

Because of their partial positive and negative
charges, polar molecules can attract each other.

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Cohesion is an attraction between molecules of the
same substance.
Because of hydrogen bonding, water is extremely
cohesive.

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Adhesion is an attraction between molecules of
different substances.

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3–2 Energy Flow Acids, Bases, and pH

Acids, Bases, and pH
A water molecule is neutral, but can react to form
hydrogen and hydroxide ions.
H2O   H+ + OH-

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The pH scale

Chemists devised a measurement system called
the pH scale to indicate the concentration of H+
ions in solution.
The pH scale ranges from 0 to 14.

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The pH Scale

At a pH of 7, the
concentration of H+
ions and OH- ions is
equal.
Sea water
Human blood
Pure water
Milk
Normal rainfall

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Acids
An acid is any compound that forms H+ ions in
solution.

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Bases

A base is a compound that produces hydroxide
ions (OH- ions) in solution.

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Buffers

The pH of the fluids within most cells in the human
body must generally be kept between 6.5 and 7.5.

Controlling pH is important for maintaining
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3–2 Energy Flow Macromolecules

Four groups of organic compounds found in living
things are:

•carbohydrates
•lipids
•nucleic acids
•proteins

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3–2 Energy Flow Carbohydrates

What is the function of carbohydrates?
Source of Energy
Structure

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Carbohydrates
Carbohydrates are compounds made up of
carbon, hydrogen, and oxygen atoms, usually in a
ratio of 1 : 2 : 1.

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Different sizes of carbohydrates:

Monosaccharides

Disaccharides

Polysaccharides

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Starches and sugars are examples of carbohydrates
that are used by living things as a source of energy.

Starch Examples:
Cellulose
Starch
Glycogen

Glucose

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3–2 Energy Flow Lipids

Lipids
Lipids are generally not soluble in water.
The common categories of lipids are:
fats
oils
waxes
steroids
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Lipids can be used to store energy. Some lipids are
important parts of biological membranes and
waterproof coverings.

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3–2 Energy Flow Nucleic Acids

Nucleic Acids
Nucleic acids are polymers assembled from
individual monomers known as nucleotides.

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Nucleotides consist of three parts:
•a 5-carbon sugar
•a phosphate group
•a nitrogenous base

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Nucleic acids store and transmit hereditary, or
genetic, information.
ribonucleic acid (RNA)

deoxyribonucleic acid (DNA)

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3–2 Energy Flow Proteins

Proteins
Proteins are macromolecules that contain
nitrogen, carbon, hydrogen, and oxygen.
• polymers of molecules called amino acids.

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Amino acids

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The portion of each amino acid that is different is a
side chain called an R-group.

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The instructions for arranging amino acids into
many different proteins are stored in DNA.

Protein
Molecule

Amino
Acids

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Some functions of proteins:
–Control rate of reactions – Enzymes
–Used to form bones and muscles
–Transport substances into or out of cells
–Help to fight disease - antibodies

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3–2 Energy Flow Energy in Reactions

Activation Energy

Chemists call the energy that is needed to get a
reaction started the activation energy.

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3–2 Energy Flow Enzymes

Enzymes
Some chemical reactions that make life possible
are too slow or have activation energies.
These chemical reactions are made possible by
catalysts.

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3–2 Energy Flow Enzymes

Enzymes speed up chemical reactions that take
place in cells.

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3–2 Energy Flow Enzyme Action

The Enzyme-Substrate Complex

Enzymes provide a site where reactants can be
brought together to react, reducing the energy
needed for reaction.
The reactants of enzyme-catalyzed reactions are
known as substrates.

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An Enzyme-Catalyzed Reaction

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Regulation of Enzyme Activity

Enzymes can be affected by any variable that
influences a chemical reaction.
• pH values
• Changes in temperature
• Enzyme or substrate concentrations

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3–2 Energy Flow The Discovery of the Cell

Scientists
Robert Hooke: looked @ slices of plant tissue and coined
name ―cells‖
Anton van Leeuwenhoek: observed single-celled living
organisms in pond water and called them Animacules. Also
observed some bacteria.
Mattheis Schleiden: looked @ plant material an concluded
all plants are made of cells
Theodor Schwann: looked @ various animal cells an
concluded all animals are made of cells
Rudolf Virchow: studied cellular reproduction an
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3–2 Energy Flow The Discovery of the Cell

The cell theory states:

•All living things are composed of cells.
•Cells are the basic units of structure and
function in living things.
•New cells are produced from existing cells.

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3–2 Energy Flow Exploring the Cell

Electron Microscopes

Electron microscopes reveal details 1000 times
smaller than those visible in light microscopes.
Electron microscopy can be used to visualize only
nonliving, preserved cells and tissues.

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Transmission electron microscopes (TEMs)

•Used to study cell structures and large protein
molecules
•Specimens must be cut into ultra-thin slices

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Scanning electron microscopes (SEMs)

•Produce three-dimensional images of cells
•Specimens do not have to be cut into thin slices

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Scanning Electron Micrograph of Neurons

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3–2 Energy Flow Prokaryotes and Eukaryotes

Prokaryotes
Prokaryotic cells have genetic material that is
not contained in a nucleus.

•Prokaryotes do not have membrane-bound
organelles
•Prokaryotic cells are generally smaller and simpler
than eukaryotic cells.
•Bacteria are prokaryotes.
•They are the same size as mitochondrion.
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Eukaryotes

Eukaryotic cells contain a nucleus in
which their genetic material is separated
from the rest of the cell.

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•Eukaryotic cells are generally larger and more
complex than prokaryotic cells.
•Eukaryotic cells contain organelles and have a
cell membrane.
•Many eukaryotic cells are highly specialized.
•DNA is in the chromosomes.
•Plants, animals, fungi, and protists are
eukaryotes.

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3–2 Energy Flow Eukaryotic Cell Structures

Animal Cell vs. Plant Cell

•Have cell walls
•Have •Have
centrioles •Similar chloroplasts
•Gain energy organelles •Use
through eating photosynthesis
for energy

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Plant Cell
Nucleolus
Nucleus
Smooth Nuclear envelope
endoplasmic
Ribosome (free)
reticulum
Rough endoplasmic
reticulum Ribosome (attached)
Cell wall
Golgi apparatus
Cell membrane

Chloroplast
Mitochondrion
Vacuole

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Animal Cell

Smooth endoplasmic
Nucleolus reticulum
Nucleus

Ribosome (free)
Nuclear envelope

Cell membrane
Rough
endoplasmic
reticulum
Ribosome (attached)

Centrioles Golgi apparatus

Mitochondrion
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3–2 Energy Flow Nucleus

Nucleus
The nucleus is the control center of the cell.

The nucleus contains nearly all the cell's DNA
and with it the coded instructions for making
proteins and other important molecules.

Nucleolus: makes ribosomes

Nuclear Pores/Envelope: allow things in/out of
nucleus
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3–2 Energy Flow Nucleus

The Nucleus

Chromatin

Nucleolus Nuclear envelope

Nuclear
pores

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3–2 Energy Flow Ribosomes

Ribosomes
One of the most important jobs carried out in the cell
is making proteins.
Proteins are assembled on ribosomes.
Ribosomes are small particles of RNA and protein
found throughout the cytoplasm.

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3–2 Energy Flow Endoplasmic Reticulum

There are two types of ER—rough and smooth.
Endoplasmic
Assembles
Reticulum components
of cell
membrane &
some
proteins

Ribosomes

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3–2 Energy Flow Golgi Apparatus

Golgi Apparatus
Proteins are activated & transported in vesicles to
their destination

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3–2 Energy Flow Vacuoles

Vacuole
Storage area of cells
Animal cells have smaller
ones than plant cells

Vacuole

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3–2 Energy Flow Mitochondria and Chloroplasts

Mitochondria
Produce energy through
cellular respiration
Powerhouse of the cell

Mitochondrion

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3–2 Energy Flow Mitochondria and Chloroplasts

Chloroplasts Chloroplast

Plants and some other
organisms contain
chloroplasts.
Chloroplasts capture
energy from sunlight and
convert it into chemical
energy in a process called
photosynthesis.

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3–2 Energy Flow Cytoskeleton

Centrioles Centrioles
Located near the
nucleus and help to
organize cell division
Only in animal cells

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3–2 Energy Flow Cell Walls

Cell Wall
Cell walls are found in plants, algae, fungi, and
many prokaryotes. The protect and support and
are located outside of the membrane.

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Cytoskeleton
The cytoskeleton is a network of protein filaments
that helps the cell to maintain its shape. The
cytoskeleton is also involved in movement.
The cytoskeleton is made up of:

•Microfilaments: movement and support of cell
•Microtubules: tracks to move organelles/vesicles

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Cytoskeleton
Cell membrane

Endoplasmic
reticulum

Microtubule

Microfilament

Ribosomes Mitochondrion
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3–2 Energy Flow Cell Membrane

Cell Membrane
The cell membrane regulates what enters & leaves the cell and
also provides protection/support; is also selectively permeable

A.k.a. plasma membrane, fluid mosaic model, phospholipid
bilayer

Made up of phospholipids:

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3–2 Energy Flow Cell Membrane

Cell Membrane

Outside of
cell <Peripheral
Protein Glycolipids
Glycoprotein>
Phospho-
lipid Bilayer

Inside of cell
(cytoplasm)
Integral Phosphate
Protein Heads & Fatty
Acid Tails
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3–2 Energy Flow Diffusion Through Cell Boundaries

Diffusion
Particles in a solution tend to move from an area
where they are more concentrated to an area
where they are less concentrated.
This process is called diffusion.
When the concentration of the solute is the same
throughout a system, the system has reached
equilibrium.

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3–2 Energy Flow Diffusion Through Cell Boundaries

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3–2 Energy Flow Osmosis

Osmosis
Osmosis is the diffusion of water through a
selectively permeable membrane.

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How Osmosis Works

Concentrated Dilute sugar
sugar solution solution (Water
(Water less more
concentrated) concentrated)

Sugar
molecules

Movement of
Selectively permeable water
membrane
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Water tends to diffuse from a highly concentrated
region to a less concentrated region.
If you compare two solutions, three terms can be
used to describe the concentrations:

hypertonic (―above strength‖).
hypotonic (―below strength‖).
isotonic (‖same strength‖)

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Osmotic Pressure
Osmosis exerts a pressure known as osmotic
pressure on the hypertonic side of a selectively
permeable membrane.

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Osmotic Pressure
Hypertonic: solution has higher solute concentration than cell
Isotonic: concentration of solutes same inside & outside of cell
Hypotonic: Solution has lower solute concentration than cell

Examples:
Blood in isotonic water = nothing
Celery in salt water = hypotonic

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3–2 Energy Flow Facilitated Diffusion

Glucose
molecules

Facilitated Diffusion

•Diffusion of
molecules thru
protein channel
•Requires energy
•Requires
concentration
gradient
Protein
channel

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3–2 Energy Flow Active Transport

Active Transport
Sometimes cells move materials in the opposite
direction from which the materials would normally
move—that is against a concentration difference.
This process is known as active transport.
Active transport requires energy.

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Molecular Transport

In active transport, small molecules and ions are
carried across membranes by proteins in the
membrane.
Energy use in these systems enables cells to
concentrate substances in a particular location,
even when diffusion might move them in the
opposite direction.

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Molecular Transport

Molecule to be carried

Active
Transport

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Endocytosis and Exocytosis
Endocytosis is the process of taking material into
the cell.

Two examples of endocytosis are:
• phagocytosis
• pinocytosis

During exocytosis, materials are forced out of the
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3–2 Energy Flow Events of the Cell Cycle

Reasons for Cell to Divide
•Larger a cell becomes, more demands cell places
on its DNA
•Cell has more trouble moving enough nutrients &
wastes across cell membrane

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Cell Cycle

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3–2 Energy Flow The Cell Cycle

The cell cycle consists of four phases:
• G1 (First Gap Phase)
• S Phase
• G2 (Second Gap Phase)
• M Phase

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Events of the Cell Cycle
During G1, the cell
• increases in size
• synthesizes new proteins and organelles

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During the S phase,
•chromosomes are replicated
•DNA synthesis takes place
Once a cell enters the S phase, it usually completes
the rest of the cell cycle.

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The G2 Phase (Second Gap Phase)
•organelles and molecules required for cell division
are produced
•Once G2 is complete, the cell is ready to start the
M phase—Mitosis

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3–2 Energy Flow Mitosis

Mitosis
Biologists divide the events of mitosis into
four phases: (PMAT)

•Prophase
•Metaphase
•Anaphase
•Telophase

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Mitosis
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Spindle
forming
Prophase

Prophase is the first and
longest phase of mitosis.
The centrioles separate
and take up positions on
opposite sides of the
nucleus.
Centromere
Chromosomes
(paired
chromatids)

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Honors Biology 1st Semester Exam Study Guide

Honors Biology 1st Semester Exam Study Guide

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Semelhante a Honors Biology 1st Semester Exam Study Guide

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Honors Biology 1st Semester Exam Study Guide