Cell Biology

Question 1

composition of a cell membrane

Answer 1

• lipid bilayer - contains protein channels, enzymes, and receptors
• cholesterol- membrane fluidity

Question 2

Electrical gradient of a cell memebrane

Answer 2

Negative inside compared to outside. 3 Na out 2 Kin based on Na/K ATP ase.
Na gradient used for cotransport of glucose, proteins and other molecules

Question 3

desmosomes/hemidesmosomes

Answer 3

adhesion molecules (cell - cell/ cell - extracellular matrix)

Question 4

tight junctions

Answer 4

cell-cell occluding junctions, form an impermeable barrier (epithelium)

Question 5

Gap junctions

Answer 5

connexin subunits, allow communication between cells

Question 6

G proteins

Answer 6

intramembrane protein, transduce signal from receptor to response enzyme

Question 7

Ligand- triggered protein kinase

Answer 7

receptor and response enzyme are a single transmembrane protein ( insulin, epidermal growth factor)

Question 8

ABO blood type antigens

Answer 8

glycolipids on cell membrane

Question 9

HLA - type antigens

Answer 9

glycoproteins (Gp) on cell membrane

Question 10

G1 cell cycle

Answer 10

• determines cell cycle length
• growth factors affect cell during G1
• cells can move to Go (quiesecent) from here

Question 11

Mitosis

Answer 11

nuclear division

• prophase: centromere attachment, spindle formation, nucleus disappears
• Metaphase: chromosome alignment
• Anaphase: chromosomes pulled apart
• Telophase: separate nucleus reforms around each set of chromosomes
• Cytokinesis: contractile ring and cleavage furrow, separation of cells

Question 12

nucleus

Answer 12

contains a double membrane, outer membrane continuous with rough endoplasmic reticulum

Question 13

nucleolus

Answer 13

inside the nucleus, no membrane, ribosomes are made here

Question 14

Transcription

Answer 14

DNA strand is used as a template by RNA polymerase for synthesis of an mRNA strand

Question 15

Transcription factors

Answer 15

• steroid hormones- binds receptor in CYTOPLASM, then acts as a transcription factor
• thyroid hormone- binds receptor in NUCLEUS
• others: AP-1, NF-kB, STAT, NFAT

Question 16

RNA polymerase

Answer 16

unwinds DNA helix, catalyzes formation of RNA-DNA helix, then releases the RNA as a single strand copy

Question 17

DNA polymerase

Answer 17

uses oligonucleotides to amplify specific ANA sequences

Question 18

Purines

Answer 18

adenine, guanine

Question 19

Pyridimines

Answer 19

cytosine, thymidine (uracil in RNA)
Guanine - cytosine H bond
Adenine - thymidine 2H bonds

Question 20

translation

Answer 20

mRNA used as a template by ribosomes for the synthesis of protein

Question 21

ribosomes

Answer 21

bind tRNAs at A site moves to P site for peptide bond formation

Question 22

glycolysis

Answer 22

1 glucose molecule generates 2 ATP and 2 pyruvate molecules

Question 23

mitochondria

Answer 23

2 membranes: krebs cyle on inner matrix, NADH/FADHs created

Question 24

Krebs cycle

Answer 24

glucose –glycolysis–> 2 pyruvate—krebs-> NADH abd FADH2 –> electron transport chain–> 36 ATP

Question 25

gluconeogensis

Answer 25

mechansim by which lactic acid (cori cycle - liver) and amino acid are converted to glucose.

Question 26

rough endoplasmic reticulum

Answer 26

synthesizes proteins that are exported

Question 27

smooth endoplasmic reticulum

Answer 27

lipid/steroid synthesis, detoxifies drugs (increased in liver and adrenal cortex

Question 28

golgi apparatus

Answer 28

modifies proteins with carbohydrates, proteins are then transported to the cellular membrane, are secreted, or are targeted to lysosomes

Question 29

lysosomes

Answer 29

have digestive enzymes that degrade engulfed particles and worn out organelles

Question 30

phagosomes

Answer 30

engulfed large particles these fuse with lysosomes to degrade

Question 31

endosomes

Answer 31

engulfed small particles - that then fuse

Question 32

Protein kinase C

Answer 32

- phosphorylates other enzymes and proteins | - activated by calcium and DAG (diacylglycerol)

Question 33

Protein Kinase A

Answer 33

- phosphorylates enzymes and proteins | - activated by CAMP

Question 34

Mysoin

Answer 34

thick filaments, uses ATP to slide along actin to cause muscle contraction

Question 35

Actin

Answer 35

thin filaments

Question 36

intermediate filaments

Answer 36

keratin (hair/nails) desmin (muscle) vimentin (fibroblasts)

Question 37

microtubules

Answer 37

form specialized cellular structures such as cilia, neuronal axons, and mitotic spindles, also involved in the transport of organelles in the cell (forms a lattice network)

Question 38

centriole

Answer 38

a specialized microtubule involved in cell division (forms spindle fibers, which pull chromosome apart)