Exam 1 Cell Bio

Question 1

Protein Disulfide Isomerase

Answer 1

catalyzes the formation and breakage of disulfide bonds

(S-S bonds in cysteine)

Question 2

Chaperone proteins

Answer 2

Proteins that guide the folding of a newly synthesized polypeptide chain

Question 3

chaperone proteins isolation chamber process

Answer 3

Partially folded protein inserted into chamber

Sequester in hydrophobic chamber with a chamber cap

Proteins folds correctly

Chamber cap dissociates and properly folded protein released

Question 4

The Unfolded Protein Response

Answer 4

sensor molecules (Ire1) in the ER lumen detect the misfolded proteins

Question 5

The Unfolded Protein Response Process

Answer 5

Translation stopped

Chaperone protein production increased

ER increases in size

Chaperones attempt refolding misfolded proteins in ER

Question 6

Proteasome

Answer 6

Complex protein that degrades misfolded proteins in the cytoplasm

Question 7

Process of Proteasome

Answer 7

1. Ubiquitin bonds to misfolded proteins to form a polyubiquitin chain
2. Proteins then targeted by polyubiquitin-site on proteasome
3. Ubiquitin recycled as slightly unfolded protein fed through central cylinder
4. Protein degraded into peptide chunks or amino acids

Question 8

Lysosomes

Answer 8

Proteins created in the ER, or at least their polypeptide components

Contain many enzymes including proteases

Maintains pH 5.0 or so

Question 9

Lysosome process

Answer 9

Proteins enters lysosome in microautophagy and encapsulated.

Low pH environment begins denaturing of proteins

Protease further breaks down protein into amino acids

Question 10

apoptosis

Answer 10

cell death

Chromatin condenses, membrane distorts and cell collapses

Question 11

mRNA Sequence

Answer 11

Decoded in Sets of Three Nucleotides to form amino acids

Question 12

PKU (Phenylketonuria)

Answer 12

caused by a single nucleotide change in the gene that encodes the enzyme Phenylalanine Hydroxylase (PAH)

Buildup of phenylalanine in the brain causes neurological damage intellectual deficiencies

Treatment includes a diet low in phenylalanine

Question 13

Phenylalanine Hydroxylase (PAH)

Answer 13

An enzyme that converts L-phenylalanine into L-tyrosine

Mutant type has a misaligned tetramerization domain

Question 14

Enzymes

Answer 14

Catalyze covalent bond breakage or formation

Question 15

Structural proteins

Answer 15

Provide mechanical support to cells and tissues

Question 16

Transport proteins

Answer 16

Carry small molecules or ions

Question 17

Motor proteins

Answer 17

Generate movement in cells and tissues

Question 18

Storage proteins

Answer 18

Store amino acids and ions

Question 19

Signal proteins

Answer 19

Carry extracellular signals from cell to cell

Question 20

Receptor proteins

Answer 20

Detect Signals and transmit them to cell’s response machinery

Question 21

Transcription Regulators

Answer 21

Bind to DNA to switch genes on and off

Question 22

Special-Purpose Proteins

Answer 22

Highly variable

Question 23

peptide bonds

Answer 23

Amino acids linked together N-C-C-N-C-C, etc

Question 24

protein

Answer 24

made of amino acids linked together into a polypeptide chain

Question 25

Three types of noncovalent bonds that help proteins fold

Answer 25

Hydrophobic forces
Hydrogen bonds
Van der Waals forces