Unit 2: AP Biology Review Questions

What organelles are in animal cells, but not plant cells?

Lymosomes, centrosomes, and flagella

What Organelles are in plant cells, but not in animal cells?

Chloroplasts, central vacuole, cell wall, and plasmodesmeta

How do ribosomes help carry out instructions encoded in DNA?

Ribosomes translate messages found on mRNA into the primary structure of polypeptides.

If a cell has a high rate of protein synthesis what organelle would you expect it to have a large number of? Why?

Mitochondria because it’s the cite of cellular respiration, which uses proteins.

Differentiate between the rough and smooth ER.

The rough ER contains ribosomes bound to the membrane. The smooth ER has no ribosomes. It synthesizes lipids, metabolizes carbohydrates, and detoxifies the cell.

Identify the main differences between prokaryotic and eukaryotic cells.

Prokaryotic cells: domains in bacteria and acrhae, DNA is in the nucleoid region, and are generally smaller in size.

Euraryotic cells: protistis, fungi, animal, and plant cells. DNA is in the nucleus and contain membrane bound organelles.

Describe the endomembrane system.

The endomembrane organelles are split into two classifications: endomembrane and energy organelles. The endomembrane organelles contain the: nuclear envelope, ER, golgi complex, lymosomes, vesicles, and plasma membrane. The energy organelles are the mitochondria and chloroplasts.

Trace the path of the protein.

1. Primary structure: Linear chain of Amino Acids (which are determined by genes). This dictates secondary and tertiary forms.

2. Secondary structure: coils and folds due to hydrogen bonding within the polypeptide backbone.

3. 3D folding due to interactions between the side chains of the amino acids. They are reinforced by hydrophobic interactions and disulfide bridges of the side chains.

4. Quaternary: association of two or more polypeptides (only found in some proteins.

Compare the main functions of microtubules, microfilaments, and intermediate filaments.

Microtubules: Hollow rod-like structures made of the protein tubulin. They serve as structural support for the movement of organelles interacting with motor proteins. They assist in the separation of chromosomes and help cell mobility.

Microfilaments: Thin, solid rods made of the protein actin. They maintain cell shape, assist in muscle contractions, and division of animal cells.

Intermediate filaments: Fibrous proteins made up of varying subunits, They maintain cell chape, anchor nucleus and organelles, and for the nuclear lamina.

Plants have a cell wall, therefore they do not have a plasma membrane. True or False.

False. They have both.

Compare the golgi complex to a warehouse. How is its function similar?

Both a warehouse and the golgi complex modifies, sorts, packages materials to be sent out. The all add labels or molecular tags.

What is autophagy? What are the steps in this process?

Autophagy is the process in lysosomes where they recycle cell organic materials which allows the cell to renew itself.

1. A membrane forms around the cellular component targeted for degradation.

2. Membrane engulfs cellular components, forming autophagosome.

3. Fuses with lymosome.

4. Hydrolytic enzymes in lymosome digest the organelles and their components are recycled. Amino acids and other small Molecules are released back into the cytoplasm.

Describe the roles of the mitochondria and chloroplasts.

Mitochondria: Site of cellular respiration. Contains: enzymes that catalyze cellular respiration and produce ATP, mitochondrial DNA, and ribosomes.

Chloroplasts: Site of photosynthesis

Differentiate between light dependent reactions and the Calvin cycle in the chloroplasts.

Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH. The Calvin cycle, which takes place in the stroma, uses energy derived from these compounds to make GA3P from CO2.

Differentiate the Krebs Cycle and the electron transport chain in the mitochondria.

The Krebs cycle produces 2 ATP and 6 NADH, for every glucose molecule entering glycolysis. The Krebs cycle takes place inside the motor mitochondria. The Krebs cycle produces CO2 that you breathe out. Electron transport produces most of the energy (34 ATP molecules, compared to only 2 ATP for glycolysis and 2 ATO for the Krebs cycle). The electron transport change takes place in the mitochondria. This stage converts the NADH into ATP.

Identify the location for: light dependent reactions, Calvin cycle, Krebs cycle, ATP synthesis, and electron transport chain.

Light Dependent reactions: Grana located in the chloroplasts

Calvin cycle: Stroma located in the chloroplasts

Krebs cycle: Mitochondria

ATP synthesis: Mitochondrial matrix

Electron transport chain: Mitochondria

Why are pigments, like chlorophyll important to plants?

Chlorophyll absorbs sunlight in plants.

Plant cells get their energy from photosynthesis, therefore they do not have a mitochondria. True or false. Why?

False. Chloroplasts convert light energy into chemical energy, and mitochondria consume the chemical energy to produce ATP.

Describe how the surface area-to-volume ratio should be in order for cells to optimize the exchange of material through the plasma membrane.

The higher the surface area-to-volume ratio is, the more efficient the exchange of material through the plasma membrane is.

Propose problems that would occur if a single cell were to keep getting larger and larger over time.

The exchange of material though the plasma membrane would not be optimal. It would lose efficiency, the cellular demand for resources would increase, and the rate of heat exchange would decrease.

The following lists will compare the surface area-to-volume ratio of three cells. Which ratio will have the most efficient exchange across its cell membrane?

a.2.0; 0.9; 1.2

b. 0.9; 0.6; 1.1

c. 0.6; 0.7; 0.5

a. 2.0

b. 1.1

c. 0.7

Which cell ratio below would be best suited for storage?

a. 4.5; 7.2; 3.1; 5.5

3.1

Calculate the SA:V ratio of the cubes. Then Identify which will have the best exchange of material through the plasma membrane.

I don’t have a picture of the cubes, but they’re in the packet :)

SA=5x5x6x1=150 V=5x5x5x1=125

SA= 2x2x6x27= 648 V= 2x2x2x27= 216
SA/V= 1.2 SA/V= 3
The second cubes have the best exchange rate

Draw a small section of a plasma membrane. Label all parts. (Done on paper no backside of this)

Paper

Why is the plasma membrane often referred to as a fluid mosaic model?

Fluid mosaic model describes the structure of cell membranes.

Fluid: the membrane is held together by weak hydrophobic interactions and can therefore move and shift.

Mosaic: comprised of many macromolecules.

What is the purpose of the plasma membrane?

The purpose of the plasma membrane is to separates internal cell environments from external environment.

What is the difference between the tails in saturated and unsaturated tails of phospholipids?

Saturated: straight

Unsaturated: kinked

What causes the kinks in the tails of phospholipids?

The double bond in unsaturated phospholipids causes the kink in tails.

What molecule embeds itself within the membrane and affects fluidity? How does it affect fluidity?

Cholesterol embeds itself within the membrane. In cold temperatures, it reduces tight packing of phospholipids which allows for fluidity. In high temperatures, it reduces movements.

Differentiate between integral proteins and peripheral proteins.

Integral proteins are embedded into the lipid bilayer and the peripheral proteins are not embedded in the lipid bilayer

How are human cells able to maintain membrane fluidity when they are in cold temperatures?

Unsaturated phospholipids have kinked tails which prevent them from tightly packing at low temperatures.

Draw an integral protein embedded within the plasma membrane. Label its hydrophobic and hydrophilic regions. (Done on paper there is no backside to this)

Paper.

What does it mean that the plasma membrane is selectively permeable?

The plasma membrane regulates what substances enter and exit.

What qualities of the plasma membrane make it selectively permeable?

Hydrophobic tails and hydrophilic heads.

Are nonpolar molecules hydrophobic or hydrophilic? What does this mean in terms of their passage across the membrane?

Nonpolar molecule are hydrophobic, which mean that they can easily cross the phospholipid bilayer of the plasma membrane.

Are polar molecules hydrophobic or hydrophilic? What does this mean in terms of their passage across the membrane?

Polar molecules are hydrophilic, which mean that they will have a harder time to cross the hydrophobic portion of the plasma membrane.

Identify the following as polar or nonpolar.

a. Carbon dioxide

b. Ions

c. Oxygen

d. Water

e. Glucose

a. Nonpolar

b. Polar

c. Nonpolar

d. Polar

e. Polar

If plant cells have a cell wall, then they cannot exchange material through their plasma membrane. True of false. Why?

False, the cell wall is around the plasma membrane and the plasmodesmata is the pore in the plant cells that allow cell-to-cell recognition

What are cell walls composed of?

Cellulose

What kind of cells have cell walls? What is the purpose of cell walls?

Plant cells. Cell walls provides shapes/structure, protection, and regulation of water intake.

What are the main difference between passive and active transport?

Active transport requires energy.

Imagine a room is a cell and someone brings in freshly popped popcorn (gas molecules). The smell slowly drifts through the room, what type of transport is this an example of?

Diffusion

Fill in the blanks: in passive transport, molecules move from blank to blank concentration.

High to Low

How are molecules able to go through diffusion? (What about them allows for this process?)

Molecules must be nonpolar because they pass directly across the membrane.

How is it possible that animal cells have a high internal concentration of potassium in comparison to their external environments?

Sodium potassium pump

What molecule is necessary for active transport?

ATP

Draw two diagrams: One of a cell going through endocytosis and one of a cell going through exocytosis.

This is one paper. There is nothing on the other side.

Paper.

Is facilitated diffusion a type of active or passive transport? Why?

Facilitated diffusion is a type of passive transport because it doesn’t require energy and the substances the proteins are helping to move down are moving down their concentration gradient.

Identify the two types of transport proteins.

Channel and carrier proteins

What are two ways water can pass through the cell membrane?

Channel proteins (aquaporins) and osmosis

How does facilitated diffusion affect the rate of diffusion?

Increases the rate of diffusion of particular molecules at low concentration.

Predict the effect on a cell if there was a mutation that changed the amino acid sequence of the proteins that make up aquaphorins.

Aquaphorins are a specific channel protein for water. If a mutation changed the amino acid sequence, water would not be able to pass through the membrane due to the hydropobic tails.

How can a chemical gradient be a source of energy for the cell (think about membrane potential)?

An unequal concentration of ions across the membrane causes an electrical charge and the cell can use that charge for energy

Contrast “concentration gradient” to “chemical gradient”

A concentration gradient is use to diffuse and is the change of the concentration of a solute between areas, however an electrochemical gradient is a change in the electric potential between areas.

Define hypertonic, isotonic, and hypotonic, Describe what would happen to a plant and animal cells if placed in one of these solutions.

Hypertonic: higher concentration outside the cell causes it to shrivel.

Isotonic: concentrations are equal both inside and outside the cell. Water diffuses into the cell at the same rate it moves out of the cell.

Hypotonic: Concentration is lower outside the cell, causing it to swell.

Circle one: a saltwater fish lives in a (Hypertonic, hypotonic, isotonic) solution. To survive in this solution the saltwater fish must consume a lot of (salt, water) and must excrete a lot of (salt, water)

Hypertonic; water; salt

If the concentration of NaCl inside a plant cell is 0.45M, which was will water diffuse if the cell is placed in a 0.25M NaCl solution?

Water will diffuse into the plant.

Calculate the solute potential of a 0.3 NaCl solution at 35 C.

-15.11 bars

Review active and passive transport.

Active transport requires ATP and moves against gradient
passive transport moves with gradient (from high to low concentration), and does not require energy

Why is compartmentalization important in cells (Use lymosomes as an example to support your reasoning)?

It helps the parts of the cell have different functions. If the lysosomes could not function in there own way the cell could not process its trash.

Discuss how both the mitochondria and chloroplast compartmentalizes processes.

The mitochondria has fold and the chloroplasts have stacked grana.

How does compartmentalization affect surface area?

Increases the surface area

Why is the mitochondria highly folded?

To increase compartmentalization.

How do eukaryotic and prokaryotic cells differ in terms of compartmentalization?

Prokaryotes do not have the same organelles and are not as advanced as eukaryotes so there is not as much compartmentalization

Describe the endosymbiotic theory.

The theory that explains the similarities mitochondria and eukaryotic have to a prokaryote. It states that an early eukaryotic cell engulfed a prokaryotic cell and became one functional organism.

What evidence is there that supports the endosymbiotic theory?

Double membrane, ribosomes, circular DNA, and are capable of function on their own.

Mitochondria and chloroplasts can still be found as free living prokaryotes. True or false?

True