Lecture 10 - Examples of Protein Functions

Question 1

What are 2 contractile proteins?

Answer 1

1. myosin

2. actin

Question 2

what are the 3 layers of a muscle?

Answer 2

1. muscle
2. fascicle (bundle fo muscle fibers
3. individual muscle fiber (cell)

Question 3

what are muscle fibers made up of?

Answer 3

contractile proteins

Question 4

motor proteins consume ______ to do _______

Answer 4

ATP

mechanical work

Question 5

what is striated muscle?

Answer 5

-tissues in skeletal muscle that are responsible for motions

Question 6

what does an electron micrograph muscle fiber show?

Answer 6

how muscle contraction works

Question 7

what are thick fibers made up of?

Answer 7

myosins

Question 8

what are thin fibers made up of?

Answer 8

actins

Question 9

pathogens (viruses, bacterial etc.) must be intercepted by _____

Answer 9

the immune system

Question 10

what are the 2 types of immune responses in humans?

Answer 10

1. cellular

2. humoral

Question 11

what is the cellular immunity response?

Answer 11

• response by T lymphocytes (T-cells)

- mature in thymus gland

Question 12

What is the humoral immunity response?

Answer 12

• response by B lymphocytes B-cells)

- produce antibodies or immunoglobulin (Ig) proteins

Question 13

what are pathogens recognized by?

Answer 13

-the antigens they carry

Question 14

what are antigens?

Answer 14

-usually carbohydrate or proteins expressed on a pathogen’s cell surface

Question 15

each antigen has a number of _____

Answer 15

epitopes

Question 16

what are epitopes

Answer 16

• antigenic determinants

- recognized by specific antibodies

Question 17

what do naive b-cells produce?

Answer 17

-fresh new antibodies

Question 18

what do memory B-cells do?

Answer 18

maintain copies of antibodies from previous infections

Question 19

what are Ig?

Answer 19

antibody proteins

Question 20

what does the antibody protein contain?

Answer 20

• two light (L) and two heavy (H) chains

- linked by disulfide bonds

Question 21

what are the different classes of Ig based on?

Answer 21

the structure of their heavy chain

Question 22

how can the Ig chains be cleaved?

Answer 22

-to separate the two Fab fragments from the Fc fragment

Question 23

where is the antigen binding site on the Ig?

Answer 23

-on the tip of the Fab arm

Question 24

what does the antigen binding site on the tip of the Fab arm have?

Answer 24

• a hypervariable amino acid sequence

- consists of V (variable) and a C (constant) region

Question 25

antibodies bind to ________

Answer 25

antigens

Question 26

what happens when antibodies bind to antigens?

Answer 26

- neutralize them by 1. signaling them for destruction by T cells 2. simply aggregating them to remove them from the cell

Question 27

what is somatic recombination?

Answer 27

-process where teh V, D, J and C regions of Ig gene are scrambled + rejoined before being transcribed and translated

Question 28

what does somatic recombination result in?

Answer 28

-variability in the Ig amino acid sequence in naive B cells

Question 29

what is affinity maturation?

Answer 29

-where the V region in the Ig gene undergoes somatic hypermutation

Question 30

what happens during affinity maturation?

Answer 30

-refinements in the antigen binding specificity of the antibody