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
2
Q
Name some examples of vesicles
A
Pinocytic Phagocytic ER Lysosomes Peroxisomes
3
Q
What are lysosomes
A
Site of breakdown for most molecule
4
Q
Where are lysosomes derived from
A
Golgi apparatus
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
6
Q
What are peroxisomes
A
Small, membrane bound organelles containing enzymes that oxidise long-chained fatty acids
7
Q
What process are peroxisomes involved with
A
Beta Oxidation
8
Q
Define beta oxidation
A
Breaking down fatty acids into two carbon fragments to generate ATP
9
Q
What compound is produced by peroxisomes after beta oxidation
A
Hydrogen peroxide
10
Q
What is hydrogen peroxide used for
A
Destroying pathogens
11
Q
Why is hydrogen peroxide broken down
A
Can be toxic to cells
12
Q
What organelle breaks hydrogen peroxide down
A
Peroxisomes
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
14
Q
Can cytoskeleton be seen under light microscopy
A
No
15
Q
What are microfilaments
A
Actin filaments that form a bracing mesh on the inner surface of the cell membrane
16
Q
What are intermediate filaments
A
Anchored transmembrane proteins which can spread tensile force through the tissues
17
Q
Name 6 types of intermediate filaments
A
- Cytokeratins
- Desmins
- Glial fibrillary acidic proteins
- Neurofilament proteins
- Nuclear laminin
- Vimentin
18
Q
Where are cytokeratins found
A
Epithelial cells
19
Q
Where are desmins found
A
Myocytes
20
Q
Where are glial fibrillary acidic proteins found
A
Astrocytes
21
Q
Where are nuclear laminin found
A
Nuclei of ALL cells
22
Q
Where are vimentin found
A
Mesodermal cells
23
Q
Give an example of a microtubule
A
Tubulin
24
Q
Describe the structure of tubulin
A
Contains alpha and beta chains arranged in groups of 13 to form hollow tubes
25
What structure do microtubules derive from
Centrosome (2 centrioles)
26
What cells are tubular found in
All except erythrocytes (no nuclei in erythrocytes)
27
What is lipofuscin
Membrane-bound orange-brown pigment that causes peroxidations of lipids (degradation) in older cells
28
Where is lipofuscin found
Heart and liver (old people)
29
Where are lipids stored
Adipocytes and liver
30
Where are glycogens stored
Cytoplasm of the liver
31
What are the basic elements that form molecular building blocks in the body
```
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Phosphate
```
32
Define the term 'macromolecules'
Simple molecules such as sugars, lipids and amino acids joining together to form large complex molecules
33
Give two examples of macromolecules
Haemoglobin, DNA and collagen
34
What monosaccharides join together to form lactose
Glucose + galactose
35
What monosaccharides join together to form sucrose
Glucose + Fructose
36
What monosaccharides join together to form maltose
Glucose + Glucose
37
What is an aldose monosaccharide
A monosaccharide containing an aldehyde group on C1
38
What is a ketone monosaccharide
One containing a ketone on C2
39
What does a typical monosaccharide consist of chemically
A C=O bond, hydroxyl groups and a carbon chain
40
What does it mean to have a chiral centre
a carbon atom with four different chemical groups attached to it
41
What are D & L monosaccharides
Optical isomers (same chemical structure but a different 3d arrangement in space)
42
What are most normal sugars (optical isomer wise)
D
43
How do cycled ring structures form
Reaction of an aldehyde or ketone with an -OH group of the same molecule
44
What type of compound is usually seen with a cycle structure
monosaccharides
45
What is a glycosidic bond
Forms between two monosaccharides (reaction with -OH to another -OH or -NH group)
46
What are O-glycosidic bonds
These form disaccharides, oligosaccharides and polysaccharides
47
What are N-glycosidic bonds
found in nucleotides and DNA
48
What are oligosaccharides
Contain 2 monosaccharides joined by an O-glycosidic bond
49
How many monosaccharides does a typical oligosaccharide have
3-12
50
Where can oligosaccharides be found
Product of polysaccharide digestion or part of protein complex
51
What are polysaccharides -1
Formed by THOUSANDS of monosaccharides joined together by glycosidic bonds
52
What glycosidic bonds can be found in starch
1,4 alpha glycosidic bonds
53
What glycosidic bonds can be found in amylopectin
Alpha 1,4 and alpha 1,6 glycosidic bonds
54
What are proteoglycans
Long-unbranched polysaccharides radiating from a core protein
55
What are polysaccharides -2
Branched polysaccharide formed from glucose residues.
56
What linkages can we see in polysaccharides-2
alpha 1,4 (between carbons)and alpha 1,6 (between side and main chain)
57
Name an example of a polysaccharide-2
Glycogen
58
Describe the chemical structure of a triglyceride
3 fatty acids bound to a glycerol molecule
59
Describe the structure of a triglyceride
Contains ester bonds
16-20 carbon atoms in each chain with a methyl group and carboxyl group at the ends
60
How does the degree of saturation affect a triglycerides melting point
Decreases as the degree of saturation increases
61
How far apart are double bonds in an unsaturated triglyceride
every 3c intervals
62
What are nucleotides
Building blocks of DNA
63
What are purine examples
Adenine and Guanine
64
What are pyrimidine examples
Thymine
| Cytosine
65
Purine vs pyrimidine
Purine - Two carbon nitrogen rings
Pyrimidine - One carbon nitrogen ring
66
What are the bonds that exist between bases
Hydrogen bonds
67
What are the bonds found between the phosphates and sugars in the sugar-phosphate backbone called
Phosphodiester bonds
68
Why is the phosphate group in a nucleotide important
Source of energy
69
How many amino acids are there in total
20
70
What part of an amino acid determines polarity
Side-chains (if they are hydrophilic or hydrophobic
71
What is the charge of glutamic acid and why
Negative
Two COO- and one NH3+
72
What optical isomer is amino acid usually seen in
L form
NOTE: Sugars are in D form
73
What factor effects the charge of the carboxyl and amino groups
pH
74
How do peptide bonds form
Condensation reaction between carboxyl and amine group
75
What determines how proteins are different to each other
Sequence of amino acids in the primary structure
76
What are 5 properties of peptide bonds
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
What is a protein
Functional and synthesised by cells
50+ AA
78
What is a peptide
Less than 50 AA
79
What is the primary structure of a protein
Sequence of amino acids in the polypeptide chain
80
What bonds can be found in the primary structure
Covalent bonds
81
What is the secondary structure of protein s
Formation of alpha helix or beta pleated sheets as hydrogen bonds form between neighbouring amino acids
82
How is an alpha helix formed
H-bonds between each carboxyl group and the H attached to the N 4 AA along the chain)
83
How are beta pleated sheets formed
By H bonds between linear regions of polypeptide chains, either from the same protein or two different proteins
84
What are super-secondary structures
Combination of secondary structures (combination of alpha and beta sub-units)
85
What is the tertiary structure of a protein
Overal 3D conformation of a protein
86
What bonds are found in the tertiary structure
H bonds, covalent and electrostatic
87
What two factors affect the structure of the tertiary structure
Temperature or pH
88
What is the quaternary structure
3D structure of a protein consists of MULTIPLE SUBUNITS
89
What are Van de Waals forces
Weak attractive/repulsive forces between atoms due to fluctuating electrical charge
90
What are hydrogen bonds
Interaction between polar groups
91
What are hydrophobic forces
Uncharges and non-polar side chains are repelled by water causing them to tightly pack together (aggregate)
92
What are ionic bonds
Electrostatic attraction between positive and negatively charged ions
93
What are disulphide bonds
very strong COVALENT bonds between sulphur atoms
94
Why do we need enzymes
Provides an alternative pathway for the reaction to occur with a lower activation energy
95
What are enzymes
Biological catalysts that allow reactions to take place at normal body temperature and conditions
96
How are enzymes regulated
By altering the conc. of substrates, products and inhibitors or activators
97
What are isoenzymes
Enzymes that have a different structure and sequence but catalyse the same reaction
98
How does temperature affect enzymes
They only function within a narrow temperature range.
99
What are coenzymes
These cannot catalyse reactions but help enzymes to do so. These bind with an enzyme protein molecule to form the active enzyme
100
What are activation-transfer enzymes
Form a covalent bond and are regenerated at the end of a reaction
101
What are oxidation-reduction enzymes
Involved with reactions where electrons are transferred from one compound to another (NAD and FAD)
102
What is myoglobin
Found in muscles and acts as a reserve supply of oxygen
-Facilitates movement of O2 into muscles
103
What structure is found in the centre of myoglobin and haemoglobin
A porphyrin ring which holds an iron atom
104
What is the porphyrin ring found in haemoglobin and myoglobin called
Haem
105
What is sickle cell anaemia
Genetic disorder that is characterised by the formation of hard, sticky, sickle-shaped red blood cells (mutation in haemoglobin )
106
What is the main function of immunoglobulins
Main function is to bind to antigens
107
Why do antibodies have to bind to antigen s
To target down cells or pathogens marked for destruction by the lysis or complement system
108
Discuss the structure of an antibody
Look in book
109
Prokaryotes vs Eukaryotes
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
Why do we need DNA
1. Acts a template and regulator for transcription and protein synthesis
111
How does DNA polymerase read the template strands
from 3' to 5' which allows DNA to be synthesised on daughter strand from 5' to 3'
112
What is the daughter strand synthesised from 5' to 3'
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
What element is found on the 3' carbon atom of DNA
An unreacted oxygen molecule
114
Why is DNA replication said to be 'semi-conservative'
Because each resulting DNA double helix retains one strand of the original DNA.
115
What is the role of topoisomerase
Unwinds the double helix by relieving the supercoils
116
What is the role of DNA helicase
Separates the DNA apart by breaking the hydrogen bonds between the bases, exposing the nucleotides
117
What is the role of DNA Polymerase
Reads 3' to 5' and synthesises DNA on daughter strand 5' to 3' and starts at a primer
118
What is a primer
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
What is a single strand binding protein
Keeps two strands of DNA apart whilst synthesis of new DNA occurs - prevents annealing to form double stranded DNA
120
What is the role of primate enzyme
RNA polymerase that synthesises the short RNA primers needed to start the strand replication process
121
What is the role of RNAse H
Removes the RNA primers that previously began DNA strand synthesis
