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Flashcards in Molecules and Genes - Shearwin Deck (85):
1

Why is water important?

makes up 2/3 of body

2

Describe 2 characteristics of water

Polar molecule: has polar covalent bonds as oxygen has stronger attraction for electrons
Hydrogen bonding: form between + and - charges in polar molecule

3

Properties of molecules that can Hydrogen bond

1. has a higher BPT than other covalent molecules
2. Is more soluble, except for long chains

4

What is a colloid?

solution containing proteins/other molecules

5

Dissociation of water (eq.)

h20 -> OH- + H+

6

What is the key pH range

7.35-7.45

7

What happens when the pH goes above/below the key range

below 7.35 = acidosis
below 7 = coma
above 7.45 = alkalosis
above 7.8 = muscle spasms

8

What are buffers?

stabilise pH by removing/adding H+ ions
(either NaHCO3 or H2CO3)

9

What is an acid? (include eq.)

solute that dissociates and releases H+ (proton donor)
H2O + CO2 H2CO3 H+ + HCO3-

10

What does diabetes 1 cause?

acidosis through production of ketones

11

What does hyperventilation cause?

alkalosis

12

What macromolecule does each of the following molecules convert to?
Sugar
Amino Acid
Nucleotides
Fatty Acids

Polysaccharide
protein
Nucleic acids
fatls/lipids/membrane

13

Name the 3 type of carbohydrates

Monosaccharide
disaccharide
polysaccharide

14

What is a monosaccharide?

Simplest sugar
Glucose
usually cyclic

15

What is a disaccharide?

2 monomers of monosacch.
Sucrose
hydrolysis of disach. = 2 monomers
dehydration of 2 mono = disach + water

16

What is a polysaccharide?

starches and glycogen
break down to use energy, join to store energy

17

Triglyceride hydrolysis (eq.)

Triglyceride + 3h20 -> glycerol + 3 fatty acids

18

Glycerol dehydration (eq)

glycerol + 3 fatty acids -> Triglyceride + 3h20

19

What is cis configuration?

h-bonds on the same sign

20

What is trans configuration?

h-bonds on seperate sides
linked to increased CAD

21

What is an Adipocyte?

fat cell/droplet
formed from glyolipid and phospholipid forming micelles

22

How is DNA formed?

dehydration synthesis of nucleotide subunits

23

What is DNA made off?

sugar phosphate backbone
bases (a, t, c, g)

24

Draw the structural unit of DNA

Draw

25

What are purines?

A and G

26

What are pyrimidines?

C and T

27

Draw the structural unit of RNA

draw

28

What are major and minor grooves in DNA? How are they formed?

the distances between the double helix
due to angle of glycosidic bonds

29

Why is A-T weaker than C-G

due to there being 2 N-H bonds in A-T compared to 3

30

Name the 3 types of RNA

mRNA
tRNA
rRNA

31

Compare RNA and DNA

RNA contains U instead of T
contains 2 -OH thus more unstable (on the 2nd)

32

What are proteins?

long chains of AA

33

What do Amino acids contain?
Draw an amino acid

H, COOH group, NH2 group and variable

34

How are peptides formed?

AA form peptides through dehydration synthesis
hydrolysis of dipeptide = AA

35

Name the 4 protein structures

Primary
secondary
tertiary
quaternaty

36

What is a primary protein?

sequence of AA

37

What is a secondary protein?

results from bonds between atoms along the chain

38

What is a tertiary protein?

results from interactions between polypeptide chain and water or R group of AA

39

What is a quaternaty protein?

interaction between various polypeptide chains

40

How many subunits does keratin and collagen have?

3 - fibrous

41

How many sub units does Haemoglobin have?

4 - globular

42

Describe the structure of Haemoglobin

4 subunits - 2 alpha and 2 beta
each subunit made up of many alpha helxes
1 haem molecule in each subunit (Haem carries O2)
Each haem molecule binds to 1 oxygen, via Fe2+

43

Why does affinity for oxygen increase, as more oxygen are binded?

without oxygen, Fe does not quite fit into the planar structure. when oxygen is binded, Fe fits, and this causes a shape change of the protein, thus 3D structure changes, resulting in more oxygen binding

44

Name the 4 types of protein dysfunction

1. altered exterior: harmless except sickle cell anemia
2. altered active site: cyanosis
3. altered tertiary structure: misfolding
4. " quaternaty structure

45

What is sickle cell anemia?

genetically transmitted
cells become trapped in blood vessels = organ damage

46

How is SSA caused?

mutation of glutamic to valine in beta chain
as glutamic is philic, whilst valine is phobic,
forms long insoluble chains of Hb, under conditions where deoxy predominates (in tissues, high altitude)
HbS will polymerise and fill cell with haemoglobin = RBC misshapen

47

What are enzymes?

allow reactions to occur under conditions necessary for life

48

What are substrates?

Reactants in enzyme reaction
binds to specific site of enzyme
enyzme-substrate complex (where it binds) and reinforced by H-bonds

49

What happens when enzyme binds to substrate? (include eq.)

enzyme undergoes temporary irreversible change in shape
S + E -> ES -> EP -> E + P

50

Velocity of reaction (eq.)

(Vmax [s] )/(Km + [s])

51

What is competitive inhibition?

Where the drug and substrate fight to bind to the same spot on the enzyme

52

What is non competitive inhibition?

Where the drug binds to a different site on the enzyme, but still removes the function of the enzyme

53

What are statins?

are competitive inhibitors which lower cholesterol

54

Name a non competitive inhibitor

Aspirin, preventing prostagladins from forming

55

What is chromatin?

DNA and histones

56

What does replication involve? And when does it occur?

It is the first process (occurs during s phase)
DNA Helicase unzips the 2 strands at A/T bonds, as they are weaker
Primase adds RNA primer to begin new strand, whilst DNA polymerase adds nucleotides as well as proof reading.

57

Draw a section of replication

Draw

58

What is a okuzaki fragment?

RNA primer and associated DNA on lagging strand

59

Why does replication have to be controlled, and why does it have proof reading abilities?

To prevent the formation of cancer, and so that mistakes are decreased.

60

What is transcription?

non template (coding) DNA strand is transcripted to RNA

61

What direction is RNA made in?

5' to 3'

62

Difference between DNA and RNA?

Uracil instead of T

63

Name the two types of genes?

Housekeeping = always turned on to allow for normal cell function
tissue specific = turned on/off due to factors; cell type, hormones, etc

64

Name the 3 stages of RNA synthesis (Transcription)

1. Initiation
2. Elongation
3. Termination

65

What is initiation?

RNA Polymerase identifies where to begin transcription of DNA. RNAP binds to promoter region, due to transcription factors

66

What is Elongation?

Ribonucleotides add to 3' end of RNA

67

What is Termination?

RNAP terminates when encounters a termination sequence

68

Explain the mechanism of Transcription?

1. RNA poly. unwinds DNA in nucleus, making a bubble
2. RNA Begins with 5' and has no proofreading mech as RNA does not last long

69

Explain how mRNA is modified? What is it called? Can you draw the mRNA?

5' cap and 3' poly(A) tail are added to mRNA (Polyadenylation)
This prevents degradation of ends by exonucleases, as well as beginning translation

70

What are exons?

coding region

71

What are introns? When are they removed? Why are they removed? Draw this proccess

non coding regions
they are removed from mRNA prior to translation
removed to provide range of proteins

72

Where does replication occur?

Nucleus

73

Where does transcription occur?

Nucleus

74

Where does translation occur?

Cytoplasm

75

What is translation?

translation of mRNA to AA

76

how many base codes code for AA?

3 (4x4x4=64)

77

Name the 3 types of AA

60 combos = general AA
3 combos = STOP codon (UAG, UGA, UAA)
1 combo = START codon (AUG or methionine)

78

difference between open reading frame (ORF) and untranslated region (UTR)

ORF is the coded region
UTR is the part that signals ribosomes to bind to start codon, ORF and stop codon.

79

What is frame shift mutation? what does this cause?

Addition and deletion of a base
Destroys the function of the protein

80

name the 3 mutations in a codon (draw a small diagram)

1. nonsense
2. Missense
3. Silent

81

What is a nonsense mutation?

protein is shorter and non functional

82

What is a missense mutation?

may change the function

83

What is silent mutation?

remains the same

84

What does aminoacyl-tRNA do?

called an adaptor molecule
reads mRNA and supplies AA
A specific AA attaches to tRNA by tRNA sythesase

85

How does AA join to a protein

ribosome made up of RNA and protein
ribosome recognises sequence in UTR, attaches, scans and insert aa in order
then catalyses reaction and joins AA by peptide bonds