BIO exam

The major functions of the plasma membrane include

recognition and communication between different cells and tissues

Turgor pressure in plant cells results when

Cells contain water vacuoles that are full of water

Freshwater protozoans react to a/an\___ environment by removing water through \___

hypotonic; a contractile vacuole

Cell products are secreted from the cell through

exocytosis

Diffusion occurs because

molecules constantly move and collide with each other

During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will

continue to move across the membrane in both directions

The diffusion of water across a selectively permeable membrane is called

osmosis

An animal cell that is surrounded by fresh water will burst because the osmotic pressure causes

water to move into the cell

Which means of particle transport requires input of energy from the cell

active transport

Which means of particle transport are shown in Figure 7-4 above

active transport

Which means of particle transport is shown in Figure 7-5 above?

endocytosis

Which of the following activities is NOT a way that unicellular organisms maintain homeostasis

cell specialization

Why do plants wilt on a hot summer day

Both loss of water and therefore lack of turgor pressure

Which of these are NOT embedded in the hydrophobic portion of the lipid bilayer at all

peripheral proteins

What kinds of molecules pass through the cell membrane most easily

small and hydrophobic

Which of the following most accurately describes the selective permeability?

Only certain molecules can cross a cell membrane

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly

CO2

Which of the following allows water to move much faster across cell membranes

aquaporins

When a cell is in equilibrium with its environment, which of the following occurs for substances that can diffuse through the cell

There is random movement of substances into and out of the cell

Which of the following is true of osmosis

In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher concentration

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.. Refer to the figure. If you examine side A after three days, you should find \____.

a decrease in the concentration of NaCl and a decrease in the water level

Five dialysis bags constructed of membrane, which is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed. Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?

C

Five dialysis bags constructed of membrane, which is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed .Which line in the graph represents the bag with the highest initial concentration of sucrose?

A

Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water\____.

is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

When a plant cell, such as one from a rose stem, is submerged in a very hypotonic solution, what is likely to occur?

The cell will become turgid.

White blood cells engulf bacteria using \____.

phagocytosis

Pinocytosis occurs in

the walls of the intestines

You are working on a team that is designing a new drug. For this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule selectively enters the target cells?

similarity of the drug molecule to other molecules transported by the target cells

What will happen to a red blood cell (RBC), which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water?

The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? The animal cell is in \____.

an isotonic solution, and the plant cell is in a hypotonic solution

Why is the cell membrane sometimes compared to mosaic art?

It is sometimes referred to as a fluid mosaic because it has many types of molecules which float along the lipids due to the many types of molecules that make up the cell membrane. For example , there are a lot of types of proteins embedded in the membrane .The liquid part is the lipid bilayer which floats along the lipids due to the many types of molecules that make up the cell.

The diagrams in Figure 7-13 above show a normal blood cell before and after it is placed in a solution. Describe what could cause the cell to react the way that it did.

The Red blood cell was put into a hypertonic solution, causing the water go out out of the cell. The act of osmosis caused this to happen, making water leave the cell.

What is the solute potential (Ys) of 3.5M sucrose solution at 22° under standard atmosphereic conditions?

Y=-85.8 bars

Zucchini cores are measured and determined to have sucrose concentration of .36 M. a. Calculate the solute potential (Ys) of thses cells at 22°b. If the zuchini cores are placed in distilled water, will water go into or out of the plant cell? Explain

Ys= -8 bars

Molecules go from areas of high concentration to low concentration. The water will go into the cell because the solute potenital of the cells is -8.8 bars and is more than the solute potential of distilled water. The cores are hypotonic in relation to the water. THe water will go into the plant cell to add pressure and balance out the negative solute potential.

Which of the following organelles would be unique for a cell that is both eukaryotic and autotrophic?

Chloroplast

After a protein is formed by a ribosome located on the endoplasmic reticulum, which organelle would the protein be transported to next?

Golgi apparatus

"Freezer burn" occurs when meat and other food stuffs are repeatedly thawed and refrozen. Each time the water in the cells freeze, long sharp crystals will damage the organelles of the cells. While frozen, virtually no chemical reactions occur in the cells. Which statement below explains the bad taste of "freezer burned" food?

The lysosomes will start auto-digestion of the damaged organelles.

Germinating seeds must utilize stored lipids to produce energy for plant growth. Peroxisomes play a vital role in lipid synthesis. A researcher wants to determine the effect of a toxic chemical on the peroxisomes of a seed. Which type of data would be most useful in answering this question?

The amount of hydrogen peroxide produced

Large membranous sacs are more prevalent in plant cells and some protists than in animal cells. These sacs in plant cells might function in

supporting the cell

Which of the following is a characteristic of chloroplast but not mitochondria?

Only chloroplasts are visible with a light microscope.

Which type of cell would contain more mitochondria?

Cardiac cells

The cells that line our respiratory tract and one-celled paramecia both have short hair-like projections called

cilia

A peroxisome and a lysosome are similar in that

both contain enzymes

Who used a compound microscope to see chambers within cork and named them "cells"?

Robert Hooke

Which of the following is NOT a principle of the cell theory?

Very few cells are able to reproduce.

Electron microscopes can reveal details

1000 times smaller than those visible in light microscopes.

Which type of microscope can produce three-dimensional images of a cell's surface?

scanning electron microscope

Looking at a cell under a microscope, you note that it is a prokaryote. How do you know?

The cell lacks a nucleus.

Which of the following enclose their DNA in a nucleus?

eukaryotes

Which of the following organisms are prokaryotes?

bacteria

Which of the following conclusions could you draw about the cell shown in Figure 7-1?

The cell is eukaryotic because it has a nucleus.

Which of the following best describes the relationship between the nucleus and the cytoplasm?

The nucleus is an organelle that is surrounded by the cytoplasm.

Which of the following is a function of the cytoskeleton?

helps a cell keep its shape

Which structures are involved in cell movement?

microtubules and microfilaments

Which structure in the cell shown in Figure 7-2 above stores materials, such as water, salts, proteins, and carbohydrates?

structure C

Which sequence correctly traces the path of a protein in the cell?

ribosome, endoplasmic reticulum, Golgi apparatus

Which organelles are involved in energy conversion?

mitochondria and chloroplasts

The primary function of the cell wall is to

support and protect the cell.

Which of the following structures serves as the cell's boundary from its environment?

cell membrane

The cell membrane contains channels and pumps that help move materials from one side to the other. What are these channels and pumps made of?

proteins

Which of the following is an example of an organ?

heart

Which list represents the levels of organization in a multicellular organism from the simplest level to the most complex level?

cell, tissue, organ, organ system

Chlamydomonas is a genus of single-celled photosynthetic algae. Which of the following is NOT a way that chlamydomonas maintains homeostasis?

The reproductive system of chlamydomonas contains specialized cells that enable the organism to reproduce both sexually and asexually.

Like animals, plants contain a hierarchical organization of interacting systems. Which of the following is an example of an organ in a plant?

leaf

The cells of all organisms contain DNA. In cells of which of the following groups is the cellular DNA enclosed in a nucleus?

eukaryotes

Microscopes can be used to explore cells. Which of the following types of microscopes is used to produce a three-dimensional image of the surface of a cell?

scanning electron microscope

A number of scientists made contributions to cell theory. Which scientist was the first to use a light microscope to observe cells in a slice of cork?

Robert Hooke

Which of these is NOT true of cells?

They are much like empty rooms.

Which of the following is a function of the nucleus?

stores DNA

Which organelle breaks down organelles that are no longer useful?

lysosome

Which organelle would you expect to find in plant cells but not animal cells?

chloroplast

Unlike the cell membrane, the cell wall is

a rigid structure.

You will NOT find a cell wall in which of these kinds of organisms?

animals

A group of similar cells that perform a particular function is called

a tissue.

List two functions of the cytoskeleton.

One function of the cytoskelaton is to help the cell maintain its shape

Another function of the cytoskelaton is the aid the cell in cell division

A third function of the cytoskeltaon is to help keep structure of the cell.

Compare a cell from a unicellular organism with a cell from a multicellular organism in terms of cell specialization.

There are many ways to look at this. A unicellular organism is made up of only one cell, while a mutlicellular organism has mutliple cells. This menas that the uncielular organism has no back up on anything, and is doing everything itself. The multiceullular organism is able to use its mutliple cells to help accompolish a task. The cell specialization of a multiceulluar organism would look much different than that of the unicellular organism. THe multicellular organism would have a group of cells doing one task and another doing a different task (making proteins, transporting fats, etc...) The unicellular organism would hvae to do all of this on its own. It would need to self sutain itself to maintain homestasis, while the multi cellular organism can maintain homestasis with the help of other cells and tissues.

Cells that need to make a lot of protein are expected to have a large number of \________________.

ribosomes

In plants, \____________________ capture energy from sunlight and convert it into chemical energy, whereas \____________________ convert chemical energy into compounds that are convenient for the cell to use.

chloroplasts, mitochondria

A classmate proposes that the mitochondria and the chrloroplasts should be classified in the "endomembrane system". Argue against the proposal.

Mitochondria and chloroplasts are not derived from the ER, nor are they connected physically or via transport vehicles to organelles of the endomembrane system. Mitochondria and chloroplasts are structurally quite different from vesicles derived from the ER, which are bound by a single membrane.

The work of scientists usually begins with

careful observations.

Information gathered from observing a plant grow 3 cm over a two-week period is called

data.

Based on your observations, you suggest that the presence of water could accelerate the growth of bread mold. This is

a hypothesis.

During a controlled experiment, a scientist isolates and tests

a single variable.

A student sees a bee on a flower. The student wonders how the bee finds flowers. This student is displaying the scientific attitude of

curiosity.

Suppose that a scientist proposes a hypothesis about how a newly discovered virus affects humans. Other virus researchers would likely

design new experiments to test the proposed hypothesis.

Suppose a scientist must choose whether to publish a report in a newspaper or in a peer-reviewed journal. What is a benefit of publishing in the journal?

The quality of the report will meet high scientific standards.

Suppose that a scientific idea is well-tested and can be used to make predictions in numerous new situations, but cannot explain one particular event. This idea is a

theory that may need revision.

Which of the following is NOT a characteristic of all living things?

ability to move

Which of the following characteristics of living things best explains why some North American birds fly south for the winter?

Living things respond to their environment.

Cells in multicellular organisms have many different sizes and shapes. These differences in cells is called cell specialization. Cell specialization allows cells to

perform different functions.

The process by which organisms keep everything inside their bodies within certain limits is called

homeostasis.

Which of the following properties or processes do we associate with living things?

all of the above

The main source of energy for producers in an ecosystem is

light energy.

For most ecosystems \_____ is (are) the ultimate source of energy, and energy leaves the ecosystem in the form of \_____.

sunlight; heat

The lowest level of biological organization that can perform all the activities required for life is the

cell-for example, a skin cell.

Which of the following statements concerning prokaryotic and eukaryotic cells is not correct?

Prokaryotic cells contain small membrane-enclosed organelles called nucleus

What is a hypothesis?

a tentative explanation that can be tested and is falsifiable

A controlled experiment is one in which

there are at least two groups, one of which does not receive the experimental treatment.

Why is it important that an experiment include a control group?

Without a control group, there is no basis for knowing if a particular result is due to the variable being tested or to some other factor.

Which of the following statements best distinguishes hypotheses from theories in science?

Hypotheses usually are relatively narrow in scope; theories have broad explanatory power.