Biology Exam 2

Which of the following statements about a typical plasma membrane is​ correct?

The two sides of the plasma membrane have different lipid and protein composition.

Which of the following best describes the structure of a biological​ membrane?

two layers of​ phospholipids, with proteins either crossing the layers or on the surface of the layers

Which of the following statements about osmosis is​ correct?

The presence of aquaporins​ (proteins that form water channels in the​ membrane) speeds up the process of osmosis.

Which of the following statements describes the role of the transport protein in facilitated​ diffusion?

Transport proteins allow solutes to move passively down their concentration gradients across the membrane.

The movement of glucose into a cell against its concentration gradient is most likely to be accomplished by which of the​ following?

cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis

Active and passive transport of solutes across a membrane typically differ in which of the following​ ways?

active transport always involves the utilization of cellular​ energy, whereas passive transport does not require cellular energy

A white blood cell engulfing a bacterium is an example of​

phagocytosis

Energy is observed in two basic​ forms: potential and kinetic. Which of the following correctly matches these forms with a source of​ energy?

potential energy with the covalent bonds of a sugar molecule

The process of cellular​ respiration, which converts simple sugars such as glucose into CO2 and​ water, is an example of​ __________.

a catabolic pathway

Which of the following statements about equilibrium of chemical reactions is​ correct?

A reaction that is at equilibrium is not capable of doing any work.

Which of the following statements best describes the first law of​ thermodynamics?

Energy cannot be created or destroyed.

A decrease in entropy is associated with which of the following types of​ reaction?

dehydration

In​ general, enzymes are what kinds of​ molecules?

proteins

An enzyme​ _____.

an organic catalyst

As a result of its involvement in a​ reaction, an enzyme​ _____.

Is unchanged

Which of the following is NOT a way in which an enzyme can speed up the reaction that it​ catalyzes?

the active site can provide heat from the environment that raises the energy content of the substrate

If an enzyme is added to a solution where its substrate and product are in​ equilibrium, what will​ occur?

Nothing; the reaction will stay at equilibrium.

Which of the following is true for all exergonic​ reactions?

The reaction proceeds with a net release of free energy.

In the process of cellular​ respiration, what is consumed and what is​ produced?

glucose is consumed and carbon dioxide is produced

Which of the following statements describing the process of glycolysis is​ correct?

It represents the first stage in the chemical oxidation of glucose by a cell.

A dehydration reaction​ (or condensation​ reaction) is the process in which

water molecules are produced as a polymer formed from monomers

The four main categories of large biological molecules present in living systems are​

​proteins, nucleic​ acids, ​ carbohydrates, and lipids

The characteristic that all lipids have in common is

none of them dissolves in water

Some regions of a polypeptide may coil or fold back on themselves. This folding is called​ __________, and the coils or folds are held in place by​ __________.

secondary​ structure, hydrogen bonds

A hydrophobic amino acid R group​ (side group) would be found where in a properly folded​ protein?

On the inside of the folded​ chain, away from water molecules

The building blocks​ ( ​ monomers) of nucleic acid molecules are called

Nucleotides

Depletion of which of the following molecules from the mitochondria will most directly inhibit the citric acid​ cycle?

NAD​+

A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid​ cycle, but together these two processes yield only a few molecules of ATP. What happens to most of the energy that the cell obtains from the oxidation of​ glucose?

it is stored in NADH and FADH2

Energy released from the electron transport chain is used to pump H+ ions into which location in eukaryotic​ cells?

mitochondrial intermembrane space

When a cell is deprived of​ oxygen, which of the following processes will be inhibited​ first?

the electron transport chain

In the absence of​ oxygen, what is the net gain of ATP for each glucose molecule that enters​ glycolysis?

two ATP

the shape of protein

determines its function

how many levels of protein structure are there?

four

primary structure

a peptide bond

secondary structure

alpha helix, and beta sheet. there’s a hydrogen bond between the backbone as connecters

tertiary structure

3D shape of polypeptide with interaction of side chains

Quaternary structure

consists of multiple polypeptide chains

DNA

A G C T

RNA

A G C U

pyrimidines

1 ring

purines

2 rings

Nucleotides are linked together by a linkage to build a polynucleotide

phosphodiester

membranes are held together by mainly

weak hydrophobic interactions

isotonic solution

the solute concentration is the same inside and outside of the cell

hypertonic solution

solute concentration is greater than that inside the cell, and as such the water leaves the cell.

hypotonic solution

solute concentration is less than that inside the cell, and as such the water enters the cell

facilitated transport

transport proteins speed up the passive movement of the molecules across the plasma membrane

active transport

the movement of substances against the concentration gradient. requires ATP.

passive transport

the movement of substances with the concentration gradient without energy

cations

are positive

anions

are negitive

catabolic pathways

release energy and break down complex molecules into simpler compounds

anabolic pathways

consume energy, and build complex molecules from simpler ones

spontaneous process

happens without energy input. Is nether slow or fast

delta G

is negative for all spontaneous reactions

exergonic reaction

proceeds with a net release of free energy

endergonic reaction

absorbs free energy from the surroundings

exergonic reaction

endergonic reaction

•Reactions in a , such as an isolated hydroelectric system, eventually and can then

closed system, reach equilibrium, do no work

oxidation

loss of electrons

reduction

gain of electrons

NAD+

is oxidized because loss of electrons

NADH

is reduced because the H gives electrons

The breakdown of organic molecules is

exergonic

Glycolysis

breaks down glucose into two molecules of pyruvate