BSC1010 Exam 2

The cell membrane is _________ which means that some things can pass through it while others can't

Selective Permeable

which of the following would you expect to pass freely through the phospholipid bilayer of the cell membrane unaided? Hint these will be molecules that share chemical characteristics with the fatty acid Sheens in the center of the bilayer.

A. Very hydrophobic molecules

B. Ions

C. very polar molecules

D. very large molecules

Very hydrophobic molecules

True or false: all cells have the same basic chemical composition and this supports the idea that all living things descend from a common ancestor.

True

cell membranes separate the Internal environment of the cell from the external environment around the cell. This separation allows ________.

A. cells to avoid bursting when placed in distilled water

B. cells to regulate their internal composition

C. cells to synthesize protein

D. cells to divide and produce more cells

B. cells to regulate their internal composition

we describe the cell membrane as a ________ because it is made-up of lipids proteins and carbohydrates which are constantly moving laterally through the membrane

A. Liquid mosaic

B. static mosaic

C. fluid mosaic

D. mosaic

C.Fluid mosaic

which of the following is true regarding the fluidity of cell membranes?

A. The ratio of saturated to unsaturated fatty acid tails in the membrane will alter its fluidity

B. if the cell membrane is too fluid the cell will be prone to breaking

C. the amount of cholesterol present in a membrane will alter its fluidity

D. cells management membrane fluidity as a way of dealing with changing temperatures

A, B, C, D

A. The ratio of saturated to unsaturated fatty acid tails in the membrane will alter its fluidity

B. if the cell membrane is too fluid the cell will be prone to breaking

C. the amount of cholesterol present in a membrane will alter its fluidity

D. cells management membrane fluidity as a way of dealing with changing temperatures

diffusion is the movement of solute that goes down their concentration gradient. T sohis means that the movement is from ___________.

A. Areas of high solute concentration to areas of low solute concentration

B. Areas of low solvent concentration to areas of high solvent concentration

C. areas of low solute concentration to areas of high solute concentration

D. areas of high solvent concentration to areas of low solvent concentration

A. Areas of high solute concentration to areas of low solute concentration

Passive transport of molecules does not require the expenditure of energy. Why?

A. The molecules are moving against the concentration gradient which is not energetically favorable

B. the molecules are moving down their concentration gradient which is not energetically favorable

C. The molecules are moving down their concentration gradient which is energetically favorable

D. the molecules are moving against the concentration gradient which is energetically favorable

C. The molecules are moving down their concentration gradient which is energetically favorable

if you drink sea water which is very salty will the cells lining your intestines take in water or release water via osmosis when the sea water enters your intestines?

A. Release

B. Absorb

A.Release

standard which of the following is true of secondary active transport? Select all that apply

A. it relies on the establishment of a concentration gradient which is achieved by primary active transport

B. coupled transport is often seen when secondary active transport occurs

C. It relies on the direct transfer of a phosphate from ATP to the protein doing the secondary active transport

D. it relies on the hydrolysis of ATP but ATP hydrolysis indirectly impacts the secondary transporter

A, B, D

A. it relies on the establishment of a concentration gradient which is achieved by primary active transport

B. coupled transport is often seen when secondary active transport occurs

D. it relies on the hydrolysis of ATP but ATP hydrolysis indirectly impacts the secondary transporter

Which of the following are true of the cytoskeleton? Select all that apply

A. it can interact with transmembrane proteins that anchor the cell to the extracellular matrix

B. it provides a framework along which motor proteins can transport molecular cargo

C. it is an extracellular structure

D. it is not static structure, i.e., certain components of the cytoskeleton can be shortened and lengthened

A, B, D

A. it can interact with transmembrane proteins that anchor the cell to the extracellular matrix

B. it provides a framework along which motor proteins can transport molecular cargo

D. it is not static structure, i.e., certain components of the cytoskeleton can be shortened and lengthened

True or false: the cell membrane is the functional barrier between the inside and the outside of the cell

True

True or false: the extracellular matrix is involved in holding cells together in tissues by essentially providing a basement onto which a layer of cells can sit on and attach

True

How many genomes does a single plant cell have?

A. 2

B. 1

C. 4

D. 3

D. 3

Which of the following is true of metabolic pathways. Select all that apply.

A. They are always exergonic overall

B. They consist of a series of reactions that are each catalyzed by a specific enzyme

C. they begin with a specific molecule (e.g. glucose) and and with a product (e.g. ATP)

D. they can be catabolic or anabolic

B, C, D

B. They consist of a series of reactions that are each catalyzed by a specific enzyme

C. they begin with a specific molecule (e.g. glucose) and and with a product (e.g. ATP)

D. they can be catabolic or anabolic

True or false: energy comes in multiple forms and can be converted from one form to another (e.g. Kinetic 2 potential or vice versa)

True

True or false: organisms are closed systems, i.e., energy and matter cannot be transferred between an Organism and its surroundings

False

The second law of thermodynamics (entropy) tells us which of the following things? Select all that apply.

A. After an energy transformation although energy is conserved not destroyed, some of it is no longer usable to do work

B. energy is neither created nor destroyed

C. cells are the fundamental units of life

D. cells must expend energy to fight against entropy (impose disorder) to exist, survive, and thrive

A, D

A. After an energy transformation although energy is conserved not destroyed, some of it is no longer usable to do work.

D. cells must expend energy to fight against entropy (impose disorder) to exist, survive, and thrive

Cells use energy coupling to do work period energy coupling uses a(n) _______ process to drive a(n) _____ process.

A. Exergonic, endergonic

B. intergonic, exergonic

C. exergonic, intergonic

D. endergonic, exergonic

A. Exergonic, endergonic

In a redox reaction, the _______ gives up electrons and becomes __________.

A. Reducing agent, oxidized

B. oxidizing agent, oxidized

C. oxidizing agent, reduced

D. reducing agent, reduced

A. Reducing agent, oxidized

Cellular respiration is a ___________ metabolic pathway.

A. Catabolic

B. Anabolic

C. Endergonic

D. None of the above

A. Catabolic

To do glycolysis we need to spend 2 ATP to start the reaction. Glycolysis produces a total of 4 ATP. What is our NET ATP at the end of glycolysis?

A. 1

B. 2

C. 3

D. 4

B. 2

True or False: NADH is the oxidized form of NAD+

False

Which is the energized form, NAD+ or NADH?

A. NAD+

B. NADH

B. NADH

Where does the carbon dioxide released as a byproduct of cellular respiration come from?

A. Oxidation of glucose

B. Oxidation of NAD+

C.Oxidation of pyruvate

A.Oxidation of glucose

What makes up a nucleotide?

A. A five carbon sugar, a phosphate, and a nitrogenous base

B. A five carbon sugar, amino acid, a base

C. A nitrogenous base, phosphate, amino acid

D. Amino acid, phospholipid, a sugar

A. A five carbon sugar, a phosphate, and a nitrogenous base

Which of the following best describes the relationship between an amino acid and their R group/side chain?

A. All side chains are the same.

B. The side chain is what differentiates one amino acid from another.

C. The side chain is what makes RNA.

D. The side chain can only determine primary structure.

B. The side chain is what differentiates one amino acid from another.

A solution with a higher solute concentration than the cell is considered:

A. Hypotonic

B. Isotonic

C. Hypertonic

D. None of the above

C. Hypertonic

True or false: Solutes that can't cross the membrane determine tonicity of a solution.

True

Which factor would most likely increase the rate of diffusion?

A.) Decreasing the temperature

B.) Increasing the concentration gradient

C.) Reducing the surface area

D.) Increasing the size of the diffusing molecules

B. Increasing the concentration gradient

Which of the following is an example of osmosis in everyday life?

A) A tea bag releasing flavor into water

B) A plant wilting when placed in a dry environment

C) Perfume spreading through a room

D) Oxygen moving from the lungs into the bloodstream

A. A tea bag releasing flavor into water

Which of the following is NOT a type of cytoskeletal filament?

A) Microtubules

B) Actin filaments

C) Intermediate filaments

D) Collagen fibers

D. Collagen fibers

Which type of cell junction primarily functions to prevent leakage between cells, creating a tight seal?

A) Gap junction

B) Desmosome

C) Tight junction

D) Adherens junction

C. Tight junction

Which of the following best describes a metabolic pathway?

A.) A series of chemical reactions occurring in a cell, with each step catalyzed by a specific enzyme.

B.) A single chemical reaction that produces a large amount of energy.

C.) A process that only occurs in the mitochondria.

D.) A random sequence of chemical reactions in a cell.

A. A series of chemical reactions occurring in a cell, with each step catalyzed by a specific enzyme.

Which of the following is true about an exergonic reaction?

A) It requires an input of energy to proceed.

B) It releases energy in the form of heat.

C) The products have a higher free energy than the reactants.

D) It is not spontaneous

B. It releases energy in the form of heat.

What is heredity information in cells primarily responsible for?

a) Energy flow within the cell

b) Passing genetic information down from cell to cell

c) The composition of the cell membrane

d) The production of proteins

B. Passing genetic information down from cell to cell

What is the primary composition of cytoplasm?

a) Carbohydrates and proteins

b) Water, salts, and organic molecules

c) Phospholipids and proteins

d) Nucleic acids and proteins

B. Water, salts, and organic molecules

Which of the following describes the function of carbohydrates on cell membranes?

a) Form the lipid bilayer

b) Provide energy to the cell

c) Cell-to-cell recognition

d) Stabilize membrane fluidity

C. Cell-to-cell recognition

What is the main function of cholesterol in animal cell membranes?

a) Forming the phospholipid bilayer

b) Transporting proteins across the membrane

c) Managing membrane fluidity

d) Providing energy to the cell

C. Managing membrane fluidity

What is the role of glycolipids in the cell membrane?

a) Stabilizing membrane fluidity

b) Helping with cell-to-cell communication

c) Acting as enzymes

d) Facilitating active transport

B. Helping with cell-to-cell communication

Which component of the biological membrane is amphipathic?

a) Cholesterol

b) Phospholipids

c) Proteins

d) Carbohydrates

B. Phospholipids

How do integral membrane proteins interact with the lipid bilayer?

a) They sit on the outside surface of the membrane

b) They are embedded in the bilayer with hydrophobic and hydrophilic regions

c) They only interact with carbohydrates

d) They help move water through the membrane

B. They are embedded in the bilayer with hydrophobic and hydrophilic regions

What is the function of transmembrane proteins?

a) To stabilize the bilayer structure

b) To assist with the movement of molecules across the membrane

c) To attach cells to one another

d) To store genetic material

B. To assist with the movement of molecules across the membrane

What effect does temperature have on membrane fluidity?

a) It increases fluidity in cold conditions

b) It decreases fluidity in cold conditions

c) It has no effect on fluidity

d) It causes the membrane to become rigid

B. It decreases fluidity in cold conditions

Which of the following is true about osmosis?

a) It involves the movement of ions

b) It is the movement of water from low to high solute concentration

c) It is the random movement of molecules in all directions

d) It only occurs in plant cells

B. It is the movement of water from low to high solute concentration

What is facilitated diffusion?

a) Movement of molecules against a concentration gradient

b) Movement of molecules through a membrane using channel proteins

c) Movement of molecules through the lipid bilayer directly

d) The use of energy to move molecules across the membrane

B. Movement of molecules through a membrane using channel proteins

Which type of molecules can pass through the cell membrane without assistance?

a) Large polar molecules

b) Small, nonpolar molecules

c) Ions

d) Proteins

B. Small, nonpolar molecules

Which of the following is an example of passive transport?

a) Active transport

b) Endocytosis

c) Facilitated diffusion

d) Phagocytosis

C. Facilitated diffusion

What does selective permeability of a membrane mean?

a) The membrane allows all substances to pass through freely

b) Only certain substances can pass through the membrane

c) The membrane prevents all substances from entering

d) The membrane only allows small molecules to pass

B. Only certain substances can pass through the membrane

What is tonicity a measure of?

a) The movement of molecules through the membrane

b) The concentration of solutes in a solution compared to another solution

c) The size of the molecules in the membrane

d) The charge of the molecules

B. The concentration of solutes in a solution compared to another solution

What is a key characteristic of a hypotonic solution?

a) It has a higher solute concentration than the cell's interior

b) It has a lower solute concentration than the cell's interior

c) It has the same solute concentration as the cell's interior

d) It causes the cell to shrivel up

B. It has a lower solute concentration than the cell's interior

Which type of membrane protein is covalently attached to lipid groups?

a) Integral membrane proteins

b) Anchored membrane proteins

c) Peripheral membrane proteins

d) Transmembrane proteins

B. Anchored membrane proteins

Which factor does NOT affect the rate of diffusion?

a) Temperature

b) The diameter of the molecules

c) The concentration gradient

d) The color of the molecules

D. The color of the molecules

How do molecules diffuse in a complex solution with many solutes?

a) All solutes diffuse together

b) Each solute diffuses based on its own concentration gradient

c) The solution remains static

d) Only nonpolar solutes diffuse

B. Each solute diffuses based on its own concentration gradient

What happens to the rate of diffusion when there is a large difference in concentration between two areas?

a) Diffusion slows down

b) Diffusion occurs more quickly

c) Diffusion stops

d) Diffusion becomes more selective

B. Diffusion occurs more quickly

What type of molecules typically do not pass through the phospholipid bilayer easily?

a) Small, nonpolar molecules

b) Water and urea

c) Ions and large polar molecules

d) Lipids

C. Ions and large polar molecules

What is the effect of cholesterol in membranes at low temperatures?

a) It increases fluidity

b) It decreases fluidity

c) It has no effect on fluidity

d) It breaks the membrane structure

A. It increases fluidity

Which of the following best describes simple diffusion?

a) Movement of molecules against the concentration gradient

b) Movement of ions through ion channels

c) Movement of molecules with the help of carrier proteins

d) Movement of molecules directly through the bilayer without assistance

D.Movement of molecules directly through the bilayer without assistance

What is the effect of surface area on diffusion?

a) Larger surface area increases the rate of diffusion

b) Larger surface area decreases the rate of diffusion

c) Surface area has no effect on diffusion

d) Surface area only affects active transport

A. Larger surface area increases the rate of diffusion

What is the primary function of nucleic acids?

A) Providing energy

B) Storing and transmitting genetic information

C) Transporting molecules

D) Forming body structures

B. Storing and transmitting genetic information

Which of the following nitrogenous bases is found in DNA but not in RNA?

A) Guanine

B) Cytosine

C) Thymine

D) Uracil

C. Thymine

Which base pairs with adenine in RNA?

A) Uracil

B) Thymine

C) Guanine

D) Cytosine

A. Uracil

What type of bond forms between the sugar and phosphate groups of adjacent nucleotides?

A) Hydrogen bond

B) Ionic bond

C) Covalent bond

D) Phosphodiester bond

D. Phosphodiester bond

In which direction do nucleic acids grow during polymerization?

A) 3’ to 5’

B) 5’ to 3’

C) 1’ to 2’

D) 2’ to 4’

B. 5’ to 3’

Which of the following is a component of a nucleotide?

A) A five-carbon sugar

B) A nitrogenous base

C) A phosphate group

D) All of the above

D.All of the above

What is the role of DNA polymerase in DNA replication?

A) It synthesizes proteins

B) It synthesizes RNA

C) It synthesizes DNA

D) It breaks down DNA

C. It synthesizes DNA

Which of the following is a characteristic of RNA?

A) Double-stranded structure

B) Contains thymine

C) Single-stranded structure

D) Contains deoxyribose

C. Single-stranded structure

What is the process of transcription?

A) DNA is copied into RNA

B) RNA is converted into proteins

C) DNA is converted into proteins

D) RNA is copied into DNA

A. DNA is copied into RNA

Which structure forms when two DNA strands pair through complementary base pairing?

A) Triple helix

C) Single strand

C) Double helix

D) None of the above

C. Double Helix

What is the basic unit of life according to cell theory?

A) Cells

B) Atoms

C) Molecules

D) Organelles

A. Cells

DNA contains uracil instead of thymine.

False

The two strands of DNA run in the opposite direction.

True

RNA is typically single-stranded.

True

The backbone of nucleic acids is made up of alternating sugars and nitrogenous bases

False

Adenine pairs with thymine in DNA.

True

RNA uses ribose sugar, while DNA uses deoxyribose sugar.

True

Phosphodiester bonds form between the sugar and phosphate groups.

True

In the central dogma of molecular biology, information flows from DNA to RNA.

True

Nucleic acids grow in the 3' to 5' direction during polymerization.

False

Enzymes are a type of protein that act as catalysts in biochemical reactions

True

Some proteins require cofactors, such as metal ions or organic molecules, to function properly.

True

Coenzymes are inorganic ions that assist proteins in catalyzing reactions.

False

Proteolysis involves breaking peptide bonds to activate proteins by hydrolysis

True

Protein structure does change once the protein is synthesized.

True

Enzymes lower the activation energy required for a chemical reaction without being consumed in the process

True

The active site of an enzyme is the part where the substrate binds to facilitate the chemical reaction.

True

Enzymes can lower the activation energy by changing the shape of the substrate.

True