IMMS: Week 2 Flashcards

1
Q

What are vesicles

A

Small, spherical membrane-bound organelles that transport and store material + exchange cell membrane between compartments

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2
Q

Name some examples of vesicles

A
Pinocytic
Phagocytic
ER
Lysosomes
Peroxisomes
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3
Q

What are lysosomes

A

Site of breakdown for most molecule

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4
Q

Where are lysosomes derived from

A

Golgi apparatus

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5
Q

What feature of lysosomes allow them to function

A

Presence of H+ - ATPase which create low pH of 5 to allow acid hydrolyses to function

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6
Q

What are peroxisomes

A

Small, membrane bound organelles containing enzymes that oxidise long-chained fatty acids

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7
Q

What process are peroxisomes involved with

A

Beta Oxidation

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8
Q

Define beta oxidation

A

Breaking down fatty acids into two carbon fragments to generate ATP

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9
Q

What compound is produced by peroxisomes after beta oxidation

A

Hydrogen peroxide

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10
Q

What is hydrogen peroxide used for

A

Destroying pathogens

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11
Q

Why is hydrogen peroxide broken down

A

Can be toxic to cells

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12
Q

What organelle breaks hydrogen peroxide down

A

Peroxisomes

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13
Q

What is the cytoskeleton

A

Filamentous proteins which brace the internal structure of the cell - helps maintain shape and internal organisation of cells

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14
Q

Can cytoskeleton be seen under light microscopy

A

No

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15
Q

What are microfilaments

A

Actin filaments that form a bracing mesh on the inner surface of the cell membrane

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16
Q

What are intermediate filaments

A

Anchored transmembrane proteins which can spread tensile force through the tissues

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17
Q

Name 6 types of intermediate filaments

A
  1. Cytokeratins
  2. Desmins
  3. Glial fibrillary acidic proteins
  4. Neurofilament proteins
  5. Nuclear laminin
  6. Vimentin
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18
Q

Where are cytokeratins found

A

Epithelial cells

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19
Q

Where are desmins found

A

Myocytes

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20
Q

Where are glial fibrillary acidic proteins found

A

Astrocytes

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21
Q

Where are nuclear laminin found

A

Nuclei of ALL cells

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22
Q

Where are vimentin found

A

Mesodermal cells

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23
Q

Give an example of a microtubule

A

Tubulin

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24
Q

Describe the structure of tubulin

A

Contains alpha and beta chains arranged in groups of 13 to form hollow tubes

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25
Q

What structure do microtubules derive from

A

Centrosome (2 centrioles)

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26
Q

What cells are tubular found in

A

All except erythrocytes (no nuclei in erythrocytes)

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27
Q

What is lipofuscin

A

Membrane-bound orange-brown pigment that causes peroxidations of lipids (degradation) in older cells

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28
Q

Where is lipofuscin found

A

Heart and liver (old people)

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29
Q

Where are lipids stored

A

Adipocytes and liver

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30
Q

Where are glycogens stored

A

Cytoplasm of the liver

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31
Q

What are the basic elements that form molecular building blocks in the body

A
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Phosphate
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32
Q

Define the term ‘macromolecules’

A

Simple molecules such as sugars, lipids and amino acids joining together to form large complex molecules

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33
Q

Give two examples of macromolecules

A

Haemoglobin, DNA and collagen

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34
Q

What monosaccharides join together to form lactose

A

Glucose + galactose

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35
Q

What monosaccharides join together to form sucrose

A

Glucose + Fructose

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36
Q

What monosaccharides join together to form maltose

A

Glucose + Glucose

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37
Q

What is an aldose monosaccharide

A

A monosaccharide containing an aldehyde group on C1

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38
Q

What is a ketone monosaccharide

A

One containing a ketone on C2

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39
Q

What does a typical monosaccharide consist of chemically

A

A C=O bond, hydroxyl groups and a carbon chain

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40
Q

What does it mean to have a chiral centre

A

a carbon atom with four different chemical groups attached to it

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41
Q

What are D & L monosaccharides

A

Optical isomers (same chemical structure but a different 3d arrangement in space)

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42
Q

What are most normal sugars (optical isomer wise)

A

D

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43
Q

How do cycled ring structures form

A

Reaction of an aldehyde or ketone with an -OH group of the same molecule

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44
Q

What type of compound is usually seen with a cycle structure

A

monosaccharides

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45
Q

What is a glycosidic bond

A

Forms between two monosaccharides (reaction with -OH to another -OH or -NH group)

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46
Q

What are O-glycosidic bonds

A

These form disaccharides, oligosaccharides and polysaccharides

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47
Q

What are N-glycosidic bonds

A

found in nucleotides and DNA

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48
Q

What are oligosaccharides

A

Contain 2 monosaccharides joined by an O-glycosidic bond

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49
Q

How many monosaccharides does a typical oligosaccharide have

A

3-12

50
Q

Where can oligosaccharides be found

A

Product of polysaccharide digestion or part of protein complex

51
Q

What are polysaccharides -1

A

Formed by THOUSANDS of monosaccharides joined together by glycosidic bonds

52
Q

What glycosidic bonds can be found in starch

A

1,4 alpha glycosidic bonds

53
Q

What glycosidic bonds can be found in amylopectin

A

Alpha 1,4 and alpha 1,6 glycosidic bonds

54
Q

What are proteoglycans

A

Long-unbranched polysaccharides radiating from a core protein

55
Q

What are polysaccharides -2

A

Branched polysaccharide formed from glucose residues.

56
Q

What linkages can we see in polysaccharides-2

A

alpha 1,4 (between carbons)and alpha 1,6 (between side and main chain)

57
Q

Name an example of a polysaccharide-2

A

Glycogen

58
Q

Describe the chemical structure of a triglyceride

A

3 fatty acids bound to a glycerol molecule

59
Q

Describe the structure of a triglyceride

A

Contains ester bonds

16-20 carbon atoms in each chain with a methyl group and carboxyl group at the ends

60
Q

How does the degree of saturation affect a triglycerides melting point

A

Decreases as the degree of saturation increases

61
Q

How far apart are double bonds in an unsaturated triglyceride

A

every 3c intervals

62
Q

What are nucleotides

A

Building blocks of DNA

63
Q

What are purine examples

A

Adenine and Guanine

64
Q

What are pyrimidine examples

A

Thymine

Cytosine

65
Q

Purine vs pyrimidine

A

Purine - Two carbon nitrogen rings

Pyrimidine - One carbon nitrogen ring

66
Q

What are the bonds that exist between bases

A

Hydrogen bonds

67
Q

What are the bonds found between the phosphates and sugars in the sugar-phosphate backbone called

A

Phosphodiester bonds

68
Q

Why is the phosphate group in a nucleotide important

A

Source of energy

69
Q

How many amino acids are there in total

A

20

70
Q

What part of an amino acid determines polarity

A

Side-chains (if they are hydrophilic or hydrophobic

71
Q

What is the charge of glutamic acid and why

A

Negative

Two COO- and one NH3+

72
Q

What optical isomer is amino acid usually seen in

A

L form

NOTE: Sugars are in D form

73
Q

What factor effects the charge of the carboxyl and amino groups

A

pH

74
Q

How do peptide bonds form

A

Condensation reaction between carboxyl and amine group

75
Q

What determines how proteins are different to each other

A

Sequence of amino acids in the primary structure

76
Q

What are 5 properties of peptide bonds

A
  1. Very stable
  2. Cleaved by proteolytic enzymes
  3. Can have partial double bonds
  4. Flexibility around C atoms not involved in bonds which allows multiple conformations
  5. Usually a preferred conformation determined by type of side chains and sequence of amino acids
77
Q

What is a protein

A

Functional and synthesised by cells

50+ AA

78
Q

What is a peptide

A

Less than 50 AA

79
Q

What is the primary structure of a protein

A

Sequence of amino acids in the polypeptide chain

80
Q

What bonds can be found in the primary structure

A

Covalent bonds

81
Q

What is the secondary structure of protein s

A

Formation of alpha helix or beta pleated sheets as hydrogen bonds form between neighbouring amino acids

82
Q

How is an alpha helix formed

A

H-bonds between each carboxyl group and the H attached to the N 4 AA along the chain)

83
Q

How are beta pleated sheets formed

A

By H bonds between linear regions of polypeptide chains, either from the same protein or two different proteins

84
Q

What are super-secondary structures

A

Combination of secondary structures (combination of alpha and beta sub-units)

85
Q

What is the tertiary structure of a protein

A

Overal 3D conformation of a protein

86
Q

What bonds are found in the tertiary structure

A

H bonds, covalent and electrostatic

87
Q

What two factors affect the structure of the tertiary structure

A

Temperature or pH

88
Q

What is the quaternary structure

A

3D structure of a protein consists of MULTIPLE SUBUNITS

89
Q

What are Van de Waals forces

A

Weak attractive/repulsive forces between atoms due to fluctuating electrical charge

90
Q

What are hydrogen bonds

A

Interaction between polar groups

91
Q

What are hydrophobic forces

A

Uncharges and non-polar side chains are repelled by water causing them to tightly pack together (aggregate)

92
Q

What are ionic bonds

A

Electrostatic attraction between positive and negatively charged ions

93
Q

What are disulphide bonds

A

very strong COVALENT bonds between sulphur atoms

94
Q

Why do we need enzymes

A

Provides an alternative pathway for the reaction to occur with a lower activation energy

95
Q

What are enzymes

A

Biological catalysts that allow reactions to take place at normal body temperature and conditions

96
Q

How are enzymes regulated

A

By altering the conc. of substrates, products and inhibitors or activators

97
Q

What are isoenzymes

A

Enzymes that have a different structure and sequence but catalyse the same reaction

98
Q

How does temperature affect enzymes

A

They only function within a narrow temperature range.

99
Q

What are coenzymes

A

These cannot catalyse reactions but help enzymes to do so. These bind with an enzyme protein molecule to form the active enzyme

100
Q

What are activation-transfer enzymes

A

Form a covalent bond and are regenerated at the end of a reaction

101
Q

What are oxidation-reduction enzymes

A

Involved with reactions where electrons are transferred from one compound to another (NAD and FAD)

102
Q

What is myoglobin

A

Found in muscles and acts as a reserve supply of oxygen

-Facilitates movement of O2 into muscles

103
Q

What structure is found in the centre of myoglobin and haemoglobin

A

A porphyrin ring which holds an iron atom

104
Q

What is the porphyrin ring found in haemoglobin and myoglobin called

A

Haem

105
Q

What is sickle cell anaemia

A

Genetic disorder that is characterised by the formation of hard, sticky, sickle-shaped red blood cells (mutation in haemoglobin )

106
Q

What is the main function of immunoglobulins

A

Main function is to bind to antigens

107
Q

Why do antibodies have to bind to antigen s

A

To target down cells or pathogens marked for destruction by the lysis or complement system

108
Q

Discuss the structure of an antibody

A

Look in book

109
Q

Prokaryotes vs Eukaryotes

A

Prokaryotes have NO nuclear membrane, and DNA arranged as a single chromosome

Eukaryotes have their DNA in the nucleus bound to protein - a chromatin complex.

110
Q

Why do we need DNA

A
  1. Acts a template and regulator for transcription and protein synthesis
111
Q

How does DNA polymerase read the template strands

A

from 3’ to 5’ which allows DNA to be synthesised on daughter strand from 5’ to 3’

112
Q

What is the daughter strand synthesised from 5’ to 3’

A

because the phosphate group on the 5’ carbon atom is used by the enzyme as a source of energy for the reaction to occur - ACTIVATION ENERGY FOR THE ENZYME

113
Q

What element is found on the 3’ carbon atom of DNA

A

An unreacted oxygen molecule

114
Q

Why is DNA replication said to be ‘semi-conservative’

A

Because each resulting DNA double helix retains one strand of the original DNA.

115
Q

What is the role of topoisomerase

A

Unwinds the double helix by relieving the supercoils

116
Q

What is the role of DNA helicase

A

Separates the DNA apart by breaking the hydrogen bonds between the bases, exposing the nucleotides

117
Q

What is the role of DNA Polymerase

A

Reads 3’ to 5’ and synthesises DNA on daughter strand 5’ to 3’ and starts at a primer

118
Q

What is a primer

A

Short strand of DNA that s the start point for DNA synthesis as DNA polymerases can only add nucleotides onto an existing strand of DNA

119
Q

What is a single strand binding protein

A

Keeps two strands of DNA apart whilst synthesis of new DNA occurs - prevents annealing to form double stranded DNA

120
Q

What is the role of primate enzyme

A

RNA polymerase that synthesises the short RNA primers needed to start the strand replication process

121
Q

What is the role of RNAse H

A

Removes the RNA primers that previously began DNA strand synthesis