Final part 1

Question 1

Testosterone is secreted by the testis and travels through the blood to enter cells throughout the body. The cytosol of target cells contains receptor molecules that bind testosterone, activating the receptor. These activated proteins enter the nucleus and turn on specific genes that control male sex characteristics. This is an example of signaling through a(n):

Answer 1

Intracellular receptor

Question 2

Which intercellular junction allows animal cells to directly communicate with each other?

Answer 2

Gap Junction

Question 3

In endergonic reactions:

Answer 3

a net input of energy is required

Question 4

Certain microorganisms have a high percentage of unsaturated fatty acids in their membrane. Because of this, these organisms:

Answer 4

are able to withstand low temperatures because their membranes do not solidify as rapidly.

Question 5

When a cell takes in bulk material by engulfing it with the use of pseudopodia or cellular extensions, the process is known as:

Answer 5

phagocytosis

Question 6

Which two functional groups are always found in amino acids?

Answer 6

carboxyl and amino groups

Question 7

Polymers of polypeptides are synthesized from monomers by which process?

Answer 7

condensation

Question 8

Which of the following is a protein?

Answer 8

collagen; not glycogen, starch, chitin or cellulose

Question 9

The tertiary structure of a protein is the:

Answer 9

unique three-dimensional shape of the fully folded polypeptide

Question 10

Which of the following descriptions best fits the class of molecules known as nucleotides?

Answer 10

a nitrogenous base, a phosphate group, and a pentose sugar

Question 11

An animal cell that lacks carbohydrate structures on the external surface of its plasma membrane would likely be impaired in which function?

Answer 11

cell-cell recognition

Question 12

According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?

Answer 12

can move laterally along the plane of the membrane

Question 13

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are?

Answer 13

hypertonic to fresh water but hypotonic to the salt solution

Question 14

Which of the following does not require phosphorylation?

Answer 14

channel proteins for facilitated diffusion

Question 15

Carriers that bind two or more molecules or ions and transport them in opposite directions are called ___________, while carriers that bind two or more molecules or ions and transport them in the same direction are called ____________.

Answer 15

antiporters; symporters

Question 16

An organism is found whose DNA content is determined to be 35% cytosine. What percentage of this organism’s DNA is adenine?

Answer 16

15%

Question 17

What are the parts of the endomembrane system?

Answer 17

nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes

Question 18

Which of the following is not likely to enter the cell by pinocytosis?

Answer 18

bacteria

Question 19

Membrane proteins that span the membrane and bind to proteins attached to the cytoskeleton on their cytoplasmic side and to fibronectins on their extracellular side form a link between the inside and the outside of the cell that permit the integration of changes inside and outside the cell. They are known as:

Answer 19

integrins

Question 20

These structures in plant cells provide an easy route for the movement of ions, small molecules like sugars and amino acids, and even macromolecules between cells:

Answer 20

plasmodesmata