Practice Exam review BIO

Question 1

List some key characteristics of RNA Polymerase

Answer 1

• RNA Polymerase is only used in Transcription
• RNA polymerases have no editing function since RNA is a transient molecule and its information is not passed on to offspring

Question 2

Deleting a nucleotide during transcription would result in__________

Answer 2

Deleting a nucleotide during transcription would result in a serious mutation called a frameshift mutation, which would completely destroy the protein’s amino acid sequence and structure

Question 3

If a nucleotide is deleted during the transcription process this event would most likely lead to:

Answer 3

the destruction of the correct reading frame.

Question 4

There is only one enzyme which can synthesize DNA

Answer 4

DNA polymerase

Question 5

EXONS

Answer 5

Exons are not removed from the transcript; they are ligated together to form the mature mRNA

Question 6

Rod cells

Answer 6

which are responsible for dim, black and white vision

NIGHT vision

Question 7

**What tissues are part of the immune response **?

Answer 7

• The thymus is the site of T-cell maturation
• The spleen is the site of B-cell maturation and also filters antigens from blood
• Lymph nodes are sites of both B- and T-cell proliferation

Question 8

Pancreas

Answer 8

The pancreas produces digestive enzymes, bicarbonate, and hormones

Question 9

B lymphocytes are involved in a process called:

Answer 9

Humoral immunity.

• Humoral immunity refers to immunity through fluid; in this case, the blood. This is where B cells have their effect: They release antibodies into the bloodstream.

Question 10

Cell-mediated immunity:

Answer 10

*** Cell-mediated immunity is the process that cytotoxic (Killer) T cells are involved in. **

Killer T cells kill “self” cells that are displaying abnormal antigen on MHC I. Helper T cells are activated by antigen displayed on MHC II, and secrete chemicals to help activate and stimulate the proliferationof killer T cells and B cells.

Question 11

Passive immunity:

Answer 11

refers to an injection of antibodies which can act as a temporary supply and help fight off a disease until a person’s own immune system can start producing antibodies

Question 12

The Complement system:

Answer 12

The complement system is a system of proteins and enzymes which, when activated, can cause cell lysis

Question 13

Excess calcitonin in the blood would most likely result in which of the following abnormalities?

Answer 13

Abnormally dense bones

** Calcitonin reduces blood calcium levels through three processes: decreasing calcium reabsorption by the kidney, decreasing calcium absorption by the small intestine, and activating osteoblasts, which store calcium as bone. This last function increases bone density**

Question 14

Under physiological conditions, which of the following amino acids is most likely to be found on the exterior of a body protein after folding is complete?

Answer 14

Hydrophilic (POLAR) residues prefer to face toward the protein exterior and are therefore likely to be found on the protein surface

ex) E- glutamate

Question 15

What elements undergo H bonding?

Answer 15

FON

Question 16

Cysteine residues form what bonds?

Answer 16

**Cysteine residues are close in space in a protein, the formation of a disulfide bond between them helps to stabilize the globular structure of the protein **

Question 17

**Fatty acid synthesis **

Answer 17

Fatty acid synthesis will only be active if the cells have enough energy and are ready to build storage molecules, especially long term storage molecules.

Question 18

Insulin

Answer 18

Insulin is released in response to elevated blood glucose and the glucose can be used for cellular respiration and storage

Question 19

**glucagon **

Answer 19

glucagon is a hormone that liberates glucose from glycogen, raises blood glucose levels, and induces fat/triglyceride breakdown

Question 20

Thyroid hormone

Answer 20

Thyroid hormone increases the basal metabolic rate of cells. This will increase the ATP consumption of the body and limit production of any long-term storage molecules

Question 21

Cortisol

Answer 21

Cortisol is a stress hormone and will lead to lipolysis to increase ATP availability in stressful situations. It will inhibit lipogenesis

Question 22

beta-oxidation occurs in what location

Answer 22

The mitochondrial matrix

Question 23

Fatty acid synthesis takes place in______

Answer 23

** cytosol **

Question 24

Where does Elongation and desaturation of fatty acids takes place?

Answer 24

**Elongation and desaturation of fatty acids takes place inside the **smooth ER **using separate enzymes.

Question 25

Missense mutation

Answer 25

A missense mutation converts a codon for one amino acid into a codon for a new amino acid, resulting in a small change within the protein’s primary sequence, and an alteration (but usually not a total elimination) of the protein’s function

Question 26

Nonsense mutation

Answer 26

A nonsense mutation creates a stop codon out of an amino acid codon, resulting in truncation of the protein and (usually) a loss of its function

Question 27

Deletion mutation

Answer 27

A deletion mutation eliminates one or more base pairs, altering the reading frame and drastically changing the amino acid sequence of the protein

Question 28

Diabetes insipidus is a condition in which an individual fails to produce antidiuretic hormone. If a person suffering from diabetes insipidus were to consume large amounts of a sugar-containing beverage, which of the following would most likely be observed after one hour?

Answer 28

An individual who cannot make ADH will be unable to reabsorb water from the collecting duct of the nephron, resulting in urine that is very dilute

Question 29

Anti-Diuretic Hormone (ADH/ Vassopressin)

Answer 29

Released from: Posterior pituitary
Target: Kidney
Affect: water retention

if ADH is present, water can be reabsorbed from the urine, thereby concentrating the urine and preventing dehydration of the body.

Question 30

Amphoteric

Answer 30

means that a molecule can act as either an acid or a base

Question 31

Phospholipids

Answer 31

Phospholipids contain a backbone (usually glycerol) with two fatty acids and a phosphate group. The phosphate group can be linked to other polar groups.

Question 32

triacylglycerides

Answer 32

Lipids that contain a glycerol backbone and three fatty acids are called triacylglycerides

Question 33

aerobic conditions

Answer 33

the presence of free oxygen

Question 34

anaerobic conditions

Answer 34

lack oxygen

Question 35

If yeast cells were cultured under aerobic conditions would there be a greater number of cells than under anaerobic respiration?

Answer 35

Yes, because the cells have more ATP available to them for reproduction

Question 36

The Gram staining in Gram-positive bacteria is due to the presence of:

Answer 36

peptidoglycan.

thick wall
stains purple

Question 37

Gram-negative

Answer 37

stains pink

not thick wall

Question 38

lactic acid is used to generate NAD+, it is only under what conditions?

Answer 38

lactic acid is used to generate NAD+, it is only under anaerobic conditions

Question 39

What organelle would be most closely associated with exocytosis of newly synthesized secretory protein?

Answer 39

Golgi apparatus

Question 40

Which types of protein are produced by the ribosomes of the rough endoplasmic reticulum?

Answer 40

Membrane-bound

Integral

Secreted

Question 41

what affect to large proteins have in plasma?

Answer 41

Serve an important role in regulation of plasma volume. For example, reducing the amount of albumin, to below-normal levels would most likely have the effect of the movement of water from the bloodstream into the tissues with resulting swelling, due to reduced osmotic pressure.

Question 42

what is true for all liquids?

Answer 42

A higher vapor pressure indicates a lower heat of vaporization.

Question 43

Diabetes insipidus, a disease of ADH deficiency, can be caused by destruction or dysfunction of the supraoptic and paraventricular nuclei of the hypothalamus. One symptom of a person with this condition might be:

Answer 43

an inability to produce concentrated urine.

Question 44

What happens in absence of ADH ?

Answer 44

• **would lead to an inability to concentrate the urine.
• Excreting a dilute urine would certainly increase plasma osmolarity, but this would not increase blood pressure.
• Plasma volume would tend to decrease due to the excess loss of water, and blood pressure would drop****

ADH has no effect on heart rate or blood glucose levels—do not confuse this disorder with diabetes mellitus

Question 45

osteoblastic activity

Answer 45

causes new bone formation as calcium is reabsorbed into the bone, thus reducing calcium serum levels, which in turn causes increased PTH activity

Question 46

PTH

Answer 46

PTH increases osteoclastic activity in order to release calcium into the blood

Question 47

RNA polymerase differs from DNA polymerase III in that RNA polymerase:

Answer 47

RNA polymerase does not require a primer and it does not have exonuclease activity. RNA polymerase synthesizes RNA in the 5’ to 3’ direction, which means it must travel 3’ to 5’ on the template strand.

Question 48

Retroviruses, which are a subclass of RNA viruses, are unique in that they contain:

Answer 48

RNA-dependent DNA polymerase.

Question 49

What are K+ leak channels?

Answer 49

K+ leak channels are the channels primarily responsible for the negative resting membrane potential. They allow many positive ions to flow out of the cell (K+ moves down its gradient, to the outside of the cell).

if they are blocked, these positive ions would remain inside the cell, driving the membrane potential in the positive direction. –>DEPOLARIZATION

Question 50

Purines

Answer 50

AG

Question 51

Pyrimidines

Answer 51

CUT