Leys Exam III

Question 1

Proteins that have crossed a membrane are

Answer 1

no longer topologically inside the cell. They must recross the membrane to get back inside the cell.

Question 2

Vesicles move from compartment to compartment within a cell by

Answer 2

budding off and membrane fusion.

Question 3

Many proteins have signal sequences at their amino terminus that direct the proteins to

Answer 3

cross the membrane. Fewer proteins have internal signal sequences.

Question 4

The nucleus is surrounded by a

Answer 4

double lipid membrane bilayer, however nuclear pores allow molecules, including proteins to pass from the cytosol into the nucleus and back.

Question 5

Larger proteins pass through

Answer 5

nuclear pores by an active process

Question 6

3Nuclear import receptors bind to

Answer 6

nuclear transport signals found on some nuclear bound proteins and facilitate transport into the nucleus.

Question 7

It generally requires multiple signals to

Answer 7

transport proteins from the cytosol into the luman of the mitochondria.

Question 8

There are multiple protein

Answer 8

translocators in the mitochondrial membrane. Each translocator interacts with a specific set of proteins.

Question 9

Transport of protein into the mitochondria requires

Answer 9

energy

Question 10

Proteins enter peroxisomes using a mechanism similar to

Answer 10

mitochondrial entry

Question 11

Proteins travel from the endoplasmic reticulum (ER), through the

Answer 11

golgi to many sites

Question 12

A signal recognition protein (SRP) binds to the

Answer 12

signal sequence during translation and directs the nascent peptide to the ER membrane.

Question 13

Proteins bound for the mitochondria are translated in the

Answer 13

cytosol and than transported through the mitochondrial membrane. A process that requires ATP.

Question 14

Proteins that are headed into or through the ER are transported through the

Answer 14

ER membrane during translation. This process does not require any additional energy.

Question 15

Carbohydrate modification of proteins in the

Answer 15

ER helps direct them to their ultimate location

Question 16

The “default pathway” if there are no other signals directing the protein to other locations, is to

Answer 16

send the protein to the cell surface

Question 17

In regulated secretory pathway cells store proteins in secretory vesicles until they are

Answer 17

signaled to release them from the cell by fusion of the vesicles with the cellular membrane

Question 18

signaled to release them from the cell by fusion of the vesicles with the cellular membrane

Answer 18

appetite, energy expenditure, genotype, digestion, metabolism, availability of food, customs and presence of disease.

Question 19

Leptin, Ghrelin and Insulin are

Answer 19

important regulators of food intake.

Question 20

Leptin circulates, in the body, at levels proportional to

Answer 20

body fat

Question 21

Leptin signals the brain that the body has

Answer 21

had enough to eat, or satiety

Question 22

Adipose tissue produces adipokines that regulate

Answer 22

metabolic processes to meet the body’s needs

Question 23

AMP and AMP/ATP regulate

Answer 23

AMP-activated kinase (AMPK) that senses cellular energy levels

Question 24

AMPK regulates

Answer 24

rate-limiting enzymes in energy-producing and using pathways.

Question 25

High levels of AMPK activity inhibit

Answer 25

energy-utilizing pathways and stimulate energy generating pathways.

Question 26

Increased Ghrelin increases

Answer 26

apetite

Question 27

Ghrelin favors accumulation of

Answer 27

lipids in the visceral fatty tissue

Question 28

Estimated average requirements (EAR) for calories changes with

Answer 28

age and sex. Estimated daily protein requirements vary with age and sex.

Question 29

The ideal amount of calorie intake in a day is

Answer 29

equal to the calorie utilization for that day.

Question 30

Recommended daily allowance (RDA) for a nutrient is a value that is

Answer 30

adequate for the great majority of individuals. The estimated average requirement (EAR) reflects amount that is adequate for half of the population.

Question 31

Different nutrients have different

Answer 31

energy content. Fat has the highest energy content per weight. Alcohol has a high-energy content

Question 32

Increases in obesity are correlated with an increase in

Answer 32

the use of high fructose corn syrup.

Question 33

High fructose corn syrup is made by

Answer 33

breaking down cornstarch into glucose using amylase followed by conversion to fructose with glucose isomerase.

Question 34

There are several potential health issues associated with comsumption of high fructose corn syrup including

Answer 34

mercury exposure, hypertension, elevated cholesterol, long-term liver damage, increased risk of diabetes and weight gain and obesity.

Question 35

Protein-calorie malnutrition causes a number of health problems including:

Answer 35

decreased protein synthesis and glucose transport, fatty liver, liver necrosis and fibrosis, depression, hypothermia, compromised immune function and would healing, decreased cardiac and renal function, loss of muscle.

Question 36

Obesity is associated with an increased risk for several conditions including

Answer 36

type 2 diabetes, hypertension and stroke, dyslipidemia, gall stones, respiratory disorders, musculoskeletal disorders and several cancers including breast, endometrial, ovarian, gall bladder and colon.

Question 37

Trans fatty acids are

Answer 37

not essential and provide no benefit to human health.

Question 38

Saturated fats increase levels of

Answer 38

LDL cholesterol (bad cholesterol

Question 39

Trans fats increase levels of

Answer 39

LDL and also lower levels of HDL (good cholesterol); thus increasing the risk of coronary heart disease

Question 40

1. Drug metabolism can take place anywhere in the body (Plasma, kidney, lung, gut wall) but

Answer 40

liver is the prime site

Question 41

1. There are three potential outcomes of drug metabolism:

Answer 41

1. 1)Increase in drug hydrophilicity and ability to be excreted (hepatic) 2)Metabolic products are less pharmacologically active than the substrate drug 3)Inactive prodrugs converted to their active forms (hepatic

Question 42

1. There are several mechanisms of Drug Resistance including:

Answer 42

1) decreased permeability 2) alteration of the target site for the drug 3) enzymatic inactivation of the drug 4) active transport of the drug out of the cell 5) amplification of the gene coding for the target of the drug.

Question 43

An increase in DNA repair activity can

Answer 43

decrease effectiveness of drugs that target DNA.

Question 44

1. Multidrug resistant results from an

Answer 44

1. increase in the amount of transporter proteins that can pump many different drugs out of the cell.

Question 45

Cell proliferation

Answer 45

the process that results in an increase of the number of cells, and is defined by the balance between cell divisions and cell loss through cell death or differentiation. Cell proliferation is increased in tumours

Question 46

Cell specialization, 3) Cell interaction

Answer 46

Duh

Question 47

the 4 essential processes needed to develop from a single cell into a multicellular organism

Answer 47

1) Cell proliferation, 2) Cell specialization, 3) Cell interaction, 4) Cell movement.

Question 48

cell movement

Answer 48

a complex phenomenon primarily driven by the actin network beneath the cell membrane, and can be divided into three general components: protrusion of the leading edge of the cell, adhesion of the leading edge and deadhesion at the cell body and rear, and cytoskeletal contraction to pull the cell