Biology

Question 1

enzymes

Answer 1

protein catalysts that accelerate reactions by reducing the activation energy without being consumed or altered by the reaction. Note that enzymes affect only the rate of reaction; they do not effect the underlying thermochemistry of the reaction or the number of products that can eventually be formed

Question 2

Calcitonin

Answer 2

hormone synthesized and released by the thyroid gland that decreases plasma Ca2+ concentration

Question 3

Tidal Volume

Answer 3

the volume of air that is normally inhaled or exhaled with each breath

Question 4

Binary Fission

Answer 4

Method of asexual reproduction by which prokaryotes divide. the circular DNA molecule replicates and then moves to opposite sides of the cell. The cell then divides into two daughter cells of equal size

Question 5

Stabilizing Selection

Answer 5

type of natural selection where the normal phenotype is favored while those outside the norm are eliminated

Question 6

synapse

Answer 6

the space between the axon terminal of one neuron and the dendrite of another neuron. Synapses are where neurotransmitters are released

Question 7

Parthenogenesis

Answer 7

The development of an unfertilized egg into an adult organism

Question 8

Citric Acid Cycle

Answer 8

The cycle begins when the two-carbon acetyl group from acetyl CoA combines with oxaloacetate to form citric acid. This product then proceeds through a series of reactions that result in the regeneration of oxaloacetate and the production of three NADH, one FADH2, and one GTP

Question 9

peptide hormones

Answer 9

hydrophilic hormones incapable of permeating the cell membrane that bind to surface receptors and act through secondary messengers

Question 10

Directional Selection

Answer 10

Type of natural selection where one extreme phenotype is favored over the normal phenotype and other extreme phenotypes

Question 11

Monohybrid Cross

Answer 11

A cross between two organisms where only one trait is being studied.

Question 12

Gluconeogenesis

Answer 12

A process in the liver by which glucose is produced using by-products of glycolysis, lipids, or fats

Question 13

Lysosome

Answer 13

membrane-bound vesicle that contains hydrolytic enzymes used for intracellular

Question 14

Leading Strand

Answer 14

During DNA replication, the strand of DNA that is continuously synthesized in the 5’ to 3’ direction. The template strand is read in the 3’ to 5’ direction

Question 15

Glycolysis

Answer 15

Through a series of enzymatic reactions in the cytoplasm, glucose is converted into two molecules of pyruvate. The energy released in this process is used to produce a net yield of two ATP and two NADH molecules

Question 16

Action Potential

Answer 16

A sharp change in the membrane potential of neurons or muscle cells caused by a change in the selective permeability to K+ and Na+ using ion-gated channels. Action potentials are all-or-none events

Question 17

Genotype

Answer 17

The genetic makeup of an individual

Question 18

Endometrium

Answer 18

the mucosal lining of the uterus where the embryo implants. Progesterone is necessary for the maintenance of the endometrium during pregnancy

Question 19

Sister Chromatids

Answer 19

After replication, each chromosome consists of two identical chromatids held together at a central region called the centromere. After the mitotic spindle pulls the sister chromatids apart, each chromatid is referred to as a chromosome

Question 20

Residual Volume

Answer 20

the amount of air that must remain in the lung at all times in order to prevent lung collapse

Question 21

Lagging Strand

Answer 21

During DNA replication, the strand of DNA that is synthesized in small fragments called Okazaki fragments and then ligated together. The Okazaki fragments are synthesized in the 5’ to 3’ direction, but the overall synthesis is in the 3’ to 5’ direction. The template strand has a 5’ to 3’ polarity

Question 22

Negative Pressure Breathing

Answer 22

The contraction of the diaphragm and the intercostal muscles increases the volume of the thoracic cavity, reducing the pressure in the intrapleural space. This decrease in pressure creates a vacuum that causes the lungs to suck in air

Question 23

Point Mutation

Answer 23

mutation in which one nucleotide base is substituted for another. The protein products are often functional

Question 24

Active Transport

Answer 24

Membrane transport that utilizes energy. Unlike other methods of transport, active transport can move particles from a region of lower concentration to a region

Question 25

Bacteriophages

Answer 25

viruses that can infect bacteria

Question 26

Facultative Anaerobe

Answer 26

an organism that make ATP by aerobic respiration if oxygen is present, but that can switch to fermentation when oxygen is not available

Question 27

Posterior Pituitary

Answer 27

Stores and releases hormones (oxytocin and ADH) synthesized by the hypothalamus. The release of these hormones is triggered by an action potential that originates in the hypothalamus

Question 28

osmoregulation

Answer 28

maintenance of water and solute concentrations

Question 29

Spongy Bone

Answer 29

Lighter and less dense than compact bone, it consists of an interconnecting lattice of bony spinucles (trabeculae). The cavities between the spicules contain bone marrow

Question 30

Zymogen

Answer 30

Enzymes that must undergo processing before it can catalyze reactions

Question 31

Sister Chromatids

Answer 31

After replication, each chromosome consists of two identical chromatids held together at a central region called the centromere. After the mitotic spindle pulls the sister chromatids apart, each chromatid is referred to as a chromosome

Question 32

Fibrin

Answer 32

Protein responsible for blood clotting

Question 33

inner cell mass

Answer 33

the group of cells in a blastocyst (mammalian blastula) that develop into the embryo

Question 34

Test cross

Answer 34

a cross between an organism of an undetermined genotype and another that is homozygous recessive for the trait of interest

Question 35

Non-competitive inhibitor

Answer 35

Molecule that inhibits the activity of an enzyme by binding to a regulatory site on the enzyme, thereby changing the conformation of the enzyme. Because these inhibitors do not directly compete with the substrate, increasing substrate concentration usually has little effect in counteracting this inhibition of the catalytic rate

Question 36

Cartilage

Answer 36

a firm, elastic, translucent connective tissue consisting of collagenous fibers embedded in chondrin. Produced by cells called chondrocytes. Cartilage is the principal component of embryonic skeletons and can harden and calcify into bone

Question 37

Passive Immunity

Answer 37

a short-lived immunity resulting from the transfer of antibodies into an individual who does not produce those antibodies

Question 38

Compact bone

Answer 38

much more dense than spongy bone, compact bone consists of haversian systems (osteons)

Question 39

chromatin

Answer 39

chromosomes in their uncoiled active state. chromatin is not visible under a light microscope

Question 40

Villi

Answer 40

fingerlike projections that extend out of the small intestine in order to increase surface area for maximum absoprtion

Question 41

Chyme

Answer 41

combination of partially digested food and acid that forms in the stomach

Question 42

Aldosterone

Answer 42

a steroid hormone produced in the adrenal cortex that increases reabsorption of sodium and water and the excretion of potassium

Question 43

Disruptive Selection

Answer 43

type of natural selection where both phenotypic extremes are favored over the normal phenotype

Question 44

Active Immunity

Answer 44

immunity resulting from the production of antibodies during a previous infection or a vaccination

Question 45

Cardiac Output

Answer 45

the total volume of blood the left ventricle pumps into circulation per minute. The cardiac output can be increased by increasing either the heart rate or the stroke volume

Question 46

Induction

Answer 46

the influence of a group of cells (sometimes called the organizer) on the development of other cells. Induction is achieved by chemical substances known as inducers

Question 47

Peristalsis

Answer 47

involuntary contractions of smooth muscle that push food through the digestive tract

Question 48

Capillaries

Answer 48

blood vessels composed of a single layer of endothelial cells, facilitating exchange between the blood and interstitial fluid

Question 49

Leydig Cells

Answer 49

also referred to as "interstitial cells of Leydig," Leydig cells are located in the testes and secrete testosterone and other androgens

Question 50

Thermoregulation

Answer 50

maintenance of a constant internal body temperature

Question 51

Monosynaptic Reflex

Answer 51

Reflex pathway that has only one synapse between the sensory neuron and the motor neuron (e.g., knee-jerk reflex).