cells

Question 1

function ribosomes

Answer 1

direct translation by reading mRNA that has been transcribed.

Question 2

subunits, rRNA molecules

describe the structure of a ribosome

Answer 2

2 subunits: large and small:
* eukaryotes: 60S (L) + 40S (S) = 80S (not additive)
* prokaryotes: 50S (L) + 30S (S) = 70S
made up of 50+ proteins and 3 rRNA molecules
* euk: 5.8S, 18S, 28S rRNA
* prok: 5S, 16S, 23S rRNA

Question 3

function cytoplasm

Answer 3

contains crucial biochemicals involved in energy generation and biosynthetic processes within the cell. e.g.: ATP, NAD, NADP

Question 4

what is ATP?

Answer 4

adenosine triphosphate: source of energy in biosynthetic reactions; synthesized during exothermic reactions

Question 5

what is NAD?

Answer 5

Nicotinamide adenine dinucleotide: an oxidant in biochemical reactions; its reduced form NADH is involved in energy metabolism

Question 6

what is NADP?

Answer 6

Nicotinamide adenine dinucleotide phosphate: a reductant used in biosynthetic reactions

Question 7

function (cell) membrane

Answer 7

• barrier between cell and environment
• structural component: gives shape, contains everything
• crucial to biochemical reactions (compartmentalization)
• fundamental to energy generation (proteins embedded in membranes)

Question 8

membrane structure

Answer 8

lipid bilayer:
* hydrophobic fatty acid ester-linked to
* hydrophilic head (phosphorylated glycerol)

Question 9

difference in membrane structure in archaea?

Answer 9

• hydrophobic fatty acid is ether-linked to hydrophilic head (far more chemically stable, can endure higher temperatures
• fatty acids are branched, made up of isoprenoids
• instead of a lipid bilayer, they join tail to tail to form a monolayer

Question 10

what is the gram stain test used for?

Answer 10

distinguishes between bacteria: gram positive and gram negative
* gram+: crystal violet is extracted: thick peptidoglycan membrane
* gram-: crystal violet cannot be extracted: thin layer of peptidoglycan and outer membrane
-> stains cause gram+ to be stained

Question 11

two types of nucleic acids

Answer 11

DNA: deoxyribonucleic acid
RNA: ribonucleic acid

Question 12

types of RNA

Answer 12

rRNA: ribosomal RNA
messenger RNA: mRNA
transfer RNA: tRNA
(small interfering RNA/microRNA: siRNA/miRNA; small nuclear RNA: snRNA; small nucleolar RNA: snoRNA; Piwi-interacting RNA: piRNA)

Question 13

structure of nucleic acids

Answer 13

• phosphate
• 5 carbon sugar (deoxyribose or ribose)

Question 14

nucleoside vs nucleotide?

Answer 14

nucleoside: sugar plus base
nucleotide: sugar, base and phosphate

Question 15

what are the nucleic acid bases (names and types)

Answer 15

Pyrimidines:
* Cytosine (2G)
* Thymine (3A)
* Uracil (3A)
Purines:
* Adenine (3T, U)
* Guanine (2C)