Biology Anatomy

Question 1

5’ cap

Answer 1

a methylated guanine nucleotide added to the 5’ end of eukaryotic mRNA. The cap is necessary to initiate translation of mRNA

Question 2

a band

Answer 2

The band of the sarcomere that extends the full
length of the thick filament. The A band includes
regions of thick and thin filament overlap, as well as a region of thick filament only. A bands alternate
with I bands to give skeletal and cardiac muscle a
striated apperance. The A band does not shorten
during muscle contraction.

Question 3

absolute refractory period

Answer 3

A period of time following an action potential during
which no additional action potential can be evoked
regardless of the level of stimulation. (usually
because Na+ channel closed whle K+ efflux)

Question 4

accessory glands

Answer 4

The three glands in the male reproductive system
that reproduce semen: the seminal vesicles, the
prostate, and the

Question 5

accessory organs

Answer 5

(1) In the GI tract, organs that play a role in
digestion but not directly part of the alimentary
canal. These include the liver, the gallbladder, the
pancreas, adn the salivary glands.

Question 6

acetylcholine ACh

Answer 6

The neurotransmitter used throughout the
parasympathetic nervous system as well as the
neuromuscular junction.

Question 7

acetlycholinesterase (AChE)

Answer 7

The enzyme that breaks down acetylcholine in the

synaptic cleft.

Question 8

Acetyl-CoA

Answer 8

The first substrate in the Krebs cycle, produced
primarily from the oxidation of pyruvate by the
pyruvate dehydrogenase complex, however
acetyl-CoA is also produced during fatty acid
oxidation and protein catabolism.

Question 9

acid hydrolases

Answer 9

Enzymes that degrade various macromolecules and that require an acidic pH to function properly. Acid hydrolases are found within the lysosomes of cells.

Question 10

acinar cells

Answer 10

Cells that make up exocrine glands, and that secrete their products into ducts. For example, in the pancreas, acinar cells secrete digestive enzyme; in the salivary glands, acinar cells secrete saliva.

Question 11

acrosome

Answer 11

A region at the head of a sperm cell that contains
digestive enzyems which, when released during the acrosome reaction, can facilitate penetration of the corona radiata of the egg, and subsequently,
fertilization

Question 12

actin

Answer 12

A contractile protein. In skeletal and cardiac muscle, actin polymerizes (along with other proteins) to form the thin filaments. Actin is involved in many contractile activities, such as cyotkinesis, pseudopod formation, and muscle contraction.

Question 13

action potential

Answer 13

A localized change in a neruon’s or musce cell’s
membrane potential that can propogate itself away
from its point of origin. Action potentials are an
all-or-none process mediated by the opening of
voltage-gated Na+ and K+ channels when the
membrane is brought to the threshold potential;
opening of the Na+ channels causes a characteristic
depolarization, while opening of the K+ channels
repolarizes the membrane.

Question 14

activation energy (Ea)

Answer 14

The amount of energy required to produce the
transition state of a chemical reaction. If the
activation energy for a reaction is very high, the
reaction occurs very slowly. Enzymes (and other
catalysts) increase reaction rates by reducing
activation energy.

Question 15

active site

Answer 15

The 3D site of an enzyme where substrates
(reactants) bind and a chemical reaction is
facilitated.

Question 16

active transport

Answer 16

The movement of molecules through the plasma
membrane against their concentration gradients.
Active transport requires input of cellular energy,
often in the form of ATP. An example is the Na+/K+
ATPase in the plasma membrane of all cells.

Question 17

adenine

Answer 17

One of the four aromatic bases found in DNA and
RNA; also a component of ATP, NADH, and FADH2. Adenine is apurine; it pairs with thymine (in DNA) and with uracil (in RNA)

Question 18

adenohypophis

Answer 18

anterior pituitary gland

Question 19

adipocyte

Answer 19

fat cell

Question 20

adrenal medulla

Answer 20

The inner region of the adrenal gland. The adrenal
medulla is part of the sympathetic nervous system, and releases epinephrine (adrenaline) and
norepinephrine into the blood when stimulated. These hormones augment and prolon the effects of
sympathetic stimulation in the body.

Question 21

adrenergic tone

Answer 21

A constant input to the arteries that keeps them
somewhat constricted to maintain a basal level of
blood pressure.

Question 22

adrenocorticotropic hormone (ACTH)

Answer 22

A tropic hormone produced by the anterior pituitary

gland that targets the adrenal cortex, stimulating it to release cortisol and aldosterone.

Question 23

afferent arteriole

Answer 23

The small artery that carries blood toward the

capillaries of the glomerulus

Question 24

afferent neuron

Answer 24

A neuron that carries information (action potentials)

to the central nervous system; a sensory neuron.

Question 25

albumin

Answer 25

A blood protein produced by the liver. Albumin
helps to mantain blood osmotic pressure (oncotic
pressure)

Question 26

aldosterone

Answer 26

The principal mineralocorticoid secreted by the
adrenal cortex. This steroid hormone targets the
kidney tubules and increases renal reabsorption of
sodium [and excretion of potassium]. (this causes
ADH to be secreted & increased water comes out,
increasing blood pressure indirectly).

Question 27

alimentary canal

Answer 27

Also known as the gastrointestinal (GI) tract of the
digestive tract, the alimentary canal is the long
muscular “tube” that includes the mouth esophagus, stomach, small intestine, and large intestine.

Question 28

allosteric regulation

Answer 28

The modification of enzyme activity through
interactino of molecules with specific sites on the
enzyme other than the active site (called allosteric
sites)

Question 29

alveolie

Answer 29

(singular alveolus.) Tiny sacs, with walls only a single cell layer thick found at the end of the respiratory bronchiole tree. Alveoli are the site of gas exchange in the respiratory system.

Question 30

allele

Answer 30

A version of a gene. For example, the gene may be
for eye color, and the allels include those for brown
eyes, those for blu e eyes, those green eyes, etc. At most, diploid organisms can posses only two alleles for a given gene, one on each of the two homologous chromosomes.

Question 31

amino acid

Answer 31

The monomer of a protein; amino acids have an amine group on one end of the molecule and a carboxylic acid group on the other, and of the of 2 different side
chains.

Question 32

amino acid acceptor site

Answer 32

The 3’ end of a tRNA molecule that binds an amino

acid. The nucleotide sequence at this end is CCA

Question 33

aminoacyl tRNA

Answer 33

A tRNA with an amino acid attached. This is made
by an animoacyl-tRNA synthetase specific to the
amino acid being attache.d

Question 34

aminion

Answer 34

A sac filled with fluid (aminotic fluid) that surrounds

and protects a developing embryo.

Question 35

amphipatic

Answer 35

The characteristics of a molecule that has both polar (hydrophilic) and non-polar hydrophobic) regions, e.g. phospholipids, bile, etc.

Question 36

amylase

Answer 36

An enzyme that digests starch into disaccharides.
Amylase is secreted by salivary glands and by the
pancreas.

Question 37

anabolism

Answer 37

The process of building complex structures out of
simpler precursors, e.g. synthesizing protiens from
amino acids.

Question 38

analagous structures

Answer 38

Physical structures in two different organism that
have funcitonal similarity due to their evoluntion in
a common environment, but have different
underlying structure. Analogous structures arise
from convergent evolution.

Question 39

anal sphincter

Answer 39

The valve that controls the release of feces from the rectum. It has an internal part made of smooth
muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).

Question 40

anaphase

Answer 40

The third phase of mitosis. During anaphase,
replicated chromosmes are split apart at their
centromeres (the sister chromatids are separated
from each other) and moved to opposite sides of the cell.

Question 41

anaphase I

Answer 41

The third phase of meiosis I. During anaphase I the
rplicated homologous chromosomes are separated
(the tetrad is split) and pulled to opposite sides of
the cell.

Question 42

anaphase II

Answer 42

The third phase of meiosis II. During anaphase II the sister chromatids are finally separated at their
centromeres and puled to opposite sides of the cell. Note that anaphase II is identical to mitotic
anaphase, except the number of chromosomes was reduced by half during meiosis I.

Question 43

androgens

Answer 43

Mal sex hormones. Testosterone is the primary androgen.

Question 44

angiotensin

Answer 44

A normal blood protein produced by the liver,
angiotensin is converted to angiotensim I by renin
(secreted by kidney when blood pressur falls).
Angiotensin I si further onverted to angiotensim II
by ACE (angiotensin converting enzyme).
Angiotensin II is a powerful systemic vasoconstrictor and stimulator of aldosterone release, both of which
result in an increase in blood pressure.

Question 45

antagonist

Answer 45

Something that acts to oppose the action of
something else. For example, muscles that move a
join in opposite direction are said to be antagonists.

Question 46

antierioir pituitary gland

Answer 46

also known as the adenohypophysis, the anterior pituitary is made of gland tissue and makes and secretes six different hormones: FSH, LH, ACTH, prolatcin, TSH, and growth hormone. the anterior pituitary is controlled by releasing and inhibiting factors form the hypothalamus