anatomy 3 and 4

In and surrounding a neuron, if sodium was absent, the diffusion of potassium would result in a resting membrane potential of

-90 mV.

What is the net number of ATP molecules that can be produced from the oxidation of a glucose molecule under anaerobic conditions?

2

The net result of a single glycolysis run is the formation of

2 NADH and 2 ATP

During glycolysis of a single glucose molecule, how many ATP are produced by substrate-level phosphorylation?

4

Translation is terminated when a stop codon is presented at the ________ site.

A

Which of the following is not an example of cells communicating through direct contact?

Cells of the hypothalamus release chemical messages to induce fever

Which of the following events does not occur in prophase of mitosis?

Chromosomes are replicated

Which of the following represents the correct order of the phases of the cell cycle?

G1 -> S -> G2 -> M

Immune system cells differentiate healthy versus unhealthy cells in the body by examining what part of the cell?

Glycocalyx

The membrane-bound organelle that is composed primarily of stacked cisternae and functions to transport and package materials that arrive from the rough endoplasmic reticulum in transport veiscles is the

Golgi apparatus.

Which of the following cells will be expected to contain the most active lysosomes?

Phagocytosing white blood cell

Which of the following represents the correct order of the phases of mitosis?

Prophase -> metaphase -> anaphase -> telophase

Which of the following will pass through a cell membrane most easily?

Small nonpolar molecules

The rate of diffusion is affected by which of the following?

Temperature, size of the molecules, and steepness of the concentration gradient

Which of the following statements is false regarding the sodium-potassium pump?

The ions in the extracellular fluid bind to the carrier protein, and the potassium attached to the carrier protein is released.

Which of the following occurs as the ribosome shifts down the mRNA by a distance of three nucleotides?

The tRNA that was in the P site moves into the E site.

Which of the following is a common feature of electron carriers?

They can be reversibly oxidized and reduced.

Which of the following statements about microtubules during anaphase is true?

Those attached to chromosomes shorten, while those that are unattached elongate.

During a fever, the body increases in temperature, which will affect internal chemical reactions by

increasing kinetic energy of the reactants, helping them overcome the activation energy.

If a cell has a relatively high energy need, you would expect it to have _________ mitochondria than a cell with a lower energy need.

more

The type of passive transport that involves the movement of water across a semipermeable membrane from a region of high water concentration to a region of low water concentration is called what?

osmosis

When water moves across a semipermeable membrane, the pressure it exerts is _____ pressure.

osmotic

Cells obtain energy by ________ food molecules such as glucose.

oxidizing

Certain white blood cells engulf microorganisms and bring them in to digest them. This process is best described as

phagocytosis.

enzymes are

proteins

Translation is the synthesis of

proteins from mRNA

Which of the following is a product of glycolysis?

pyruvate

Exocytosis is a process by which cells

release substances from the cell via vesicles.

Active transport

requires energy in the form of ATP.

The organelles responsible for protein synthesis are known as __________ and the organelles that assist with the breakdown of proteins are called __________.

ribosomes; proteasomes

A red blood cell placed in a hypertonic medium will

shrink

Which of the following binds to the active site of an enzyme?

substrate

Facilitated diffusion is used to transport

sugars and amino acids.

When sugar is mixed with water, equilibrium is reached when

the dissolved sugar molecules are evenly distributed throughout the solution.

A 5% urea solution is hypotonic to a 10% urea solution.

true

ATP being broken down to ADP and phosphate is an example of a chemical reaction.

true

Cytokinesis in cells occurs by means of a cleavage furrow.

true

Diffusion is one of the processes whereby materials are exchanged between a cell and its environment.

true

During glycolysis, a six-carbon sugar diphosphate molecule is split into two 3-carbon sugar phosphate molecules.

true

Facilitated diffusion requires a specific transporter for a specific molecule

true

If a cell is placed in an isotonic medium, there will be no net movement of water.

true

If the material the cell takes in is liquid, the process is termed pinocytosis.

true

Low-density lipoproteins are brought into the cell by receptor-mediated endocytosis.

true

Lysosomes function in the destruction and recycling of old organelles.

true

Mitosis and cytoplasmic division result in the formation of two genetically identical cells.

true

NADH serves as an electron carrier that can donate its hydrogen to other molecules

true

The RNA transcript being produced by the RNA polymerase is complementary to the template strand of the DNA.

true

The enzymes found in the lysosomes were formed in the endoplasmic reticulum.

true

Whenever a molecule is oxidized, another molecule must be reduced.

true

Chemical bonds are a form of potential energy

true?

Active transport moves a solute

up its concentration gradient, that is, from a low concentration to a high one.

Facilitated diffusion requires

carrier proteins

The breaking of old chemical bonds and forming of new ones is called a

chemical reaction

In a cell that is not dividing, the unwound, filamented mass of DNA and associated proteins is(are) called

chromatin.

The division of the cytoplasm is called

cytokinesis

The uptake of material through the plasma membrane by the formation of a vesicle is _______, whereas the fusion of a vesicle with the plasma membrane and the release of its contents outside of the cell is called __________.

endocytosis; exocytosis

Reactions that release energy are called

exergonic reactions.

Active transport is able to move substances without the expenditure of energy.

false

Active transport moves substances from an area of high concentration to an area of low concentration of that substance.

false

An enzyme can only bind one reactant at a time.

false

An enzyme speeds up a chemical reaction in the cell, but can only be used once.

false

Centromeres divide during metaphase.

false

The codon of tRNA is complementary to the anticodon of mRNA.

false

The first amino acid enters through the A site.

false

The sodium-potassium exchange pump moves three potassium ions out of the cell and two sodium ions into the cell with each cycle.

false

Under aerobic conditions, the end-product of glycolysis is further reduced to yield more ATP.

false

Unlike simple diffusion, facilitated diffusion requires energy expenditure by the cell.

false

Unwinding of the DNA during transcription is the result of the activity of a helicase enzyme downstream of the RNA polymerase.

false

An information-containing segment of DNA that codes for the production of a molecule of RNA, which in most cases goes on to play a role in the synthesis of one or more proteins, is known as a(n)

gene.

Lysosomes are membrane-bound vesicles that arise from the

golgi apparatus

The lysosome contains ________ enzymes.

hydrolytic

Facilitated diffusion occurs

in either direction depending on the concentration gradient of the molecule.

Total ATP produced from one glucose molecule is 38. Why is the net value only 30?

ATP is used to bring pyruvate and NADH into the mitochondrion from the cytosol.

What is the molecule that enters the citric acid cycle?

Acetyl coenzyme A

How is negative feedback control of multienzyme complexes turned off?

As the product concentration decreases, the complex is no longer inhibited.

Which of the following correctly represents the mechanism of enzyme function?

E + S -> E-S -> E-P -> E + P

Why does pyruvate need to be converted to lactic acid in order for glycolysis to continue in the absence of oxygen?

In the absence of oxygen, NADH is not converted to NAD+ by the electron transport chain, and NAD+ levels fall.

The optimum temperature for most enzymes is around body temperature. If the body temperature is slightly elevated, what effect will this have on enzymatic reactions?

Increased reaction rates

Which of the following statements about receptor-mediated endocytosis is true?

It involves clathrin-coated pits.

___________ are the hollow structures formed from protein subunits that perform a variety of roles in cell division and in the structure of organelles; _____________ are small fibrils that support the plasma membrane and the shape of the cell.

Microtubules, microfilaments

Which of the following best describes the reduction of the coenzyme NAD+?

NAD+ + H -> NADH

Active transport requires

a carrier protein on the surface of the cell.

a hydrogen atom consists of

a proton and an electron

Fatty acids and some amino acids are converted directly into _____________ for ATP production.

acetyl coA

The sodium-potassium exchange pump is an example of

active transport

As concentration of substrate is increased in a reaction catalyzed by an enzyme, the reaction rate will stop increasing once saturation is reached because

all enzymes are actively engaged in a reaction.

Building glycogen from glucose molecules is an example of

anabolism

Membrane proteins that penetrate deeply into the lipid bilayer and can possibly extend from one surface to the other are called __________ proteins whereas other proteins that are attached to either the inner or the outer surface of the lipid bilayer are called __________ proteins.

integral; peripheral

A resting membrane potential

is due to a charge difference across the cell membrane.

Maltase is an enzyme that breaks down maltose. If a maltase enzyme has just completed catalyzing the decomposition of maltose, then

it is available to catalyze the same reaction with another maltose molecule.

Which of the following molecules is produced, along with the oxidation of NADH, when oxygen levels are limited?

lactate

Under anaerobic conditions, the end-product of glycolysis is converted to

lactic acid

Lingual lipase is an enzyme with an optimum pH around 5. This is __________ than the optimum pH of most enzymes in the body.

lower

The __________ on the surface of a cell increase surface area, while the __________ assist with the movement of substances across the surface.

microvilli; cilia

The result of __________ is the division of a cell's chromosomes into two new nuclei, each of which has the same amount and type of DNA as the original nucleus. The division of the cell's cytoplasm is called __________and occurs with the production of two new cells.

mitosis; cytokinesis

Simple diffusion is defined as the movement of

molecules from areas of higher concentration to areas of lower concentration.