BIO EXAM #2

The cell theory states

all cells come only from other cells.

According to cell theory

new cells arise only from preexisting cells.

Proteins are processed and modified in the interior of the

rough endoplasmic reticulum.

Which cellular structure is responsible for packaging materials with the cell?

Golgi apparatus.

In order to digest materials within a cell, the material to be digested must fuse with

a lysosome.

This organelle absorbs and converts oxygen while releasing CO2 and water?

mitochondria.

Cellular respiration is best associated with the

mitochondrion.

Which of the following is NOT evidence supporting the endosymbiotic theory?

the vacuoles can "come and go" across the plasma membrane.

The nucleus..

is found in eukaryotes, stores genetic material, and contains chromatin.

The nucleus

has a double membrane.

This structure has hereditary material inside it

mitochondrion, nucleus, and chloroplast.

Which of the following would be found as part of all cells?

DNA, plasma membrane, and ribosomes.

A flagellum is able to bend due to being made of ______________ that can bend by sliding past one another under the influence of the motor protein _____________.

microtubules/dynein.

The innermost membrane of the chloroplast is referred to as the

thylakoid membrane.

Imagine starting in the innermost space of the chloroplast and moving outward until leaving the chloroplast and entering the cytoplasm. What is the starting points an proper order of things you would move through?

thylakoid space - thylakoid membrane - stroma - inner membrane - outer membrane

Which of the following is NOT a function of the cell membrane?

It serves as a site for protein synthesis

According to the fluid-mosaic model of membrane structure

proteins float inside or within the phospholipid bilayer.

The plasma membrane is composed of

phospholipids and proteins.

Proteins do NOT pass through cell membranes because

they are very large molecules.

Permeability refers to

the extent to which a membrane allows a substance to pass through.

Which statement is FALSE concerning movement of molecules across the cell membrane?

Lipid molecules do not pass through easily.

If 0.9% NaCl were isotonic to a cell, then

1.0% would be hypertonic.

If you have a 10% sugar solution and a 35% sugar solution, how does the 10% solution compare to the 35% solution?

hypotonic

The term hypertonic means

a higher solute concentration.

An isotonic solution means that the solute concentration outside the cell

is the same as inside the cell.

Which is true of facilitated transport by carrier proteins?

It is represented by the glucose carrier that can transport hundreds of molecules a second.

Carrier molecules are required for

both facilitated diffusion AND active transport.

When a substance moves from an area of low concentration to an area of high concentration while using energy, the process is termed

active transport.

If a cell lacks ATP, which of the following processes would cease to operate immediately?

sodium/potassium pump

When an intestinal cell ingests substances inside very small vesicles that can only be seen with an electron microscope, this is

pinocytosis

Receptor-mediated endocytosis involves all of the following EXCEPT

secretion of materials from a cell.

Which of the following refers to materials only leaving the cell?

exocytosis

Which condition must be met for diffusion to occur?

a concentration difference

channel protein

allows molecules to move through a membrane through space provided by the protein

carrier protein

interacts and binds to a molecule to help it move across a membrane, usually requiring a change in protein shape

cell recognition protein

glycoproteins that allow cells of the immune systems determine if a cell belongs in the body or is an invader

receptor protein

binds to a specific extracellular molecule to bring about a change within the cell

enzymatic protein

catalyze specific reactions at the cell membrane

Following is a list of examples of the forms of movement of molecules across a membrane. Choose only those that require energy input from the cell whose membrane is directly involved.

• Insulin starts out in a vesicle inside a beta cell of the pancreas. When blood sugar level rises the vesicle moves to the cell membrane and fuses with the cell membrane.

• Ldl cholesterol receptors fill up in a coated pit and the pit is pulled into the cell and made into a vesicle.

• The cell uses a sodium-potassium pump to create a high concentration of sodium ions outside the cell.

Glucose levels go up in the bloodstream after a meal. Beta cells of the pancreas detect the elevated glucose levels. This causes them to secrete insulin protein into the bloodstream. How is this secretion accomplished?

Motor proteins drag insulin-containing vesicles to the cell membrane along microtubules.

The GLUT protein

moves glucose across a membrane by facilitated diffusion.

Which statement most accurately describes the second law of thermodynamics?

Energy cannot be changed from one form to another without a loss of usable energy.

Which of the following statements most accurately describes the first law of thermodynamics?

Energy can be neither created nor destroyed but it can be changed from one form to another.

Which of the following is NOT a correct statement about the second law of thermodynamics and entropy?

Carbon dioxide and water form glucose without the input of energy.

Occasionally someone claims to have built a machine that can run forever, producing as much energy as it consumes. This has always been disproved because it violates

the second law of thermodynamics.

The high energy bond in ATP that is used by cells is found in or between

the phosphate groups.

ATP contains

an adenine base, a ribose sugar, and three phosphate groups.

The main reason that ATP is considered the energy currency in cells is because it

contains accessible energy in phosphate bonds.

During an enzymatic reaction, what happens to the enzyme?

The enzyme and the substrate form a temporary complex.

Enzymes are specific. This means that they

have a particular substrate.

Which of the following statements is true about enzymes?

They catalyze only one specific type of reaction.

Which is true about energy of activation?

Adding the correct enzyme can lower the energy of activation.

Each enzyme has a particular substrate because enzymes

have active sites complementary in shape to their substrates.

The function of an enzyme is to

increase the rate of a metabolic reaction.

Which of the following statements is not true concerning enzymatic activity?

As the temperature increases, most enzymatic reactions will still proceed at the same rate.

If you wished to increase enzyme activity, you would do all of the following except

decrease the temperature.

If an enzymatic reaction was controlled by feedback inhibition, we would expect it to stop

as soon as a critical level of end product builds up.

In feedback inhibition of a metabolic pathway, where does the inhibitor bind?

to the enzyme of the first reaction

The location in which the enzyme and substrate complexes is called the

active site.

If A -> B -> C -> D -> E represents a metabolic pathway, then letter E would be

a product.

In which of the following ways is the enzyme inhibitor warfarin used?

• rat poison

• anticoagulant medicine

Which of the following can act a an enzyme cofactor?

• iron

• vitamines

• NAD+

Some metabolic reactions require that one molecule undergoes a reaction that causes it to lose energy and that energy is then transfered to a new chemical bond on another molecule. This describes

a coupled reaction.

If you give a child a surgary snack you might notice that they become hyperactive right afterward. Much of the sugar in the blood can be quickly absorbed by the neuronal cells of the brain where the glucose is quickly broken down to create ATP. This is an example of which factor affecting rates of enzymatic reactions?

Substrate Concetration

While paddling your canoe down a river you notice many turtles laying on logs in the sun. This is an example of which factor affecting rates of enzymatic reactions?

Temperature

Which is NOT a correct attribute of a metabolic pathway?

A constant supply of new enzymes must be produced to keep the metabolic pathway active.

We often say that we need food for energy. In a biological sense, is this correct?

Yes, because the food we eat has potential energy in its structure and this chemical energy can be converted into mechanical energy.

Cellular respiration does NOT include which of the following events?

light reactions

Which molecules are the reactants or substrates for aerobic respiration?

oxygen and glucose

Which molecules are the products of aerobic respiration?

carbon dioxide and water

Which of the following is a substrate of cellular respiration?

glucose

Which of the following does not describe the role of NAD+ in cellular respiration?

It is broken down to CO2 and water.

What role does NAD+ play in cellular respiration?

It is a coenzyme.

What are the input requirements of glycolysis?

ATP, NAD+, glucose, and ADP

The final products of glycolysis are

pyruvate, ATP, and NADH + H+.

Where does glycolysis take place within the cell?

cytoplasm

Choose the one correct statement?

Glycolysis breaks glucose down to two pyruvate molecules.

Muscles undergo fermentation when

no oxygen is available.

Pyruvate can be converted to lactate instead of going to the preparatory reaction. Why does this occur?

Oxygen is not available.

Why do organisms without oxygen need to convert pyruvate to lactate?

in order to regenerate NAD+

What phase(s) of cellular respiration produce(s) NADH?

glycolysis, preparatory reaction, and citric acid cycle

Which stage(s) will produce carbon dioxide in cellular respiration?

both the preparatory reaction and the citric acid cycle

The largest number of ATP molecules is produced in which phase of cellular respiration?

electron transport chain

Pyruvate is converted to a two-carbon acetyl group attached to coenzyme A (CoA), and CO2 is given off. This phase is called

the preparatory reaction.

Which of the following statements is NOT true?

The citric acid cycle begins and ends with pyruvate.

Which pathway in cellular respiration will produce ATP, NADH, and carbon dioxide?

citric acid cycle

The production of ATP as a result of an electrochemical gradient is called

chemiosmosis.

Why does chemiosmosis require a membrane?

to separate two compartments of the cell to allow for gradient formation

What is the final electron acceptor at the end of the electron transport chain in respiration?

Oxygen

Which molecules donate electrons to the electron transport chain of respiration?

NADH and FAD

Where is NAD+ converted to NADH?

Cytoplasm and Matrix of the Mitochondrion

ATP and ADP have a strong negative charge. How could that get into and out of the mitochondrion?

Through a membrane transport protein.

What are the products of photosynthesis?

oxygen and carbohydrate

The raw materials or reactants of the photosynthetic process include

carbon dioxide and water.

At the cellular level, photosynthesis occurs within

the chloroplast.

Solar energy is captured by

pigments.

Which of the following statements is TRUE concerning sunlight radiation used for photosynthesis?

Only the red, blue, and violet wavelengths of visible light are used for photosynthesis.

Why are plant leaves green?

They reflect green wavelengths of light.

The metabolic events that move electrons from water to NADP+ are referred to as what?

noncyclic electron pathway

Water is split and oxygen is released in

the noncyclic electron pathway.