IMMS (cells + molecular building blocks + DNA/RNA) Flashcards
1
Q
What is the role of Golgi apparatus?
A
mediates protein and lipid sorting to a specific site
2
Q
What is lipofuscin?
A
Yellow-brown pigment made from the lipid containing residues of lysosomal digestion
3
Q
define macromolecule
A
Large, biologically important molecules inside cells
4
Q
What is the general formula for carbohydrate
A
CnH2nOn
5
Q
How many sugar molecules for mono, disaccharides, oligosaccharides, polysaccharides
A
Mono- 1
di - 2
oligo - 3-12
poly- 13+
6
Q
Name of bond between sugar molecules
A
glycosidic
7
Q
Do monosaccharides generally exist as ring structures
A
Yes
reaction of the aldehyde or ketone group with a hydroxyl group of the same molecule
8
Q
`Why/where are oligosaccharides found
A
products of digestion of polysaccharides, or part of complex protein/lipids
9
Q
what are the names of the different glycosidic bonds found between sugars or nucleotides
A
sugars- O- glycosidic bonds
nucleotides- N- glycosidic bond
10
Q
Fatty acid melting points are HIGHER or LOWER with fewer saturated bonds
A
LOWER
melting point decreases with degree of unsaturation
11
Q
Name components of triglyceride
A
3 fatty acids + glycerol
12
Q
phospholipids components
A
- hydrophilic phosphate head, hydrophobic hydrocarbon tail
- glycerol, 2 fatty acids, phosphate group
13
Q
What are the two types of lipoproteins
A
HDL
LDL
14
Q
Is HDL or LDL good?
A
HDL
15
Q
Why is HDL good and LDL bad
A
HDL= good as transports cholesterol to liver to be metabolised
LDL= bad as transports cholesterol to the cells
16
Q
What makes up a nucleotide?
A
nitrogenous base + sugar + phosphate
17
Q
Which amino acids are purines?
A
adenine and guanine
18
Q
what bond connects the sugar to the base in a nucleotide
A
N- glycosidic
19
Q
what is nucleotide triphosphate? (NTP)
A
nucleotide with 3 molecules of phosphate attached.
20
Q
what bonds the sugar to the phosphate group on a nucleotide ?
A
ester bond
21
Q
what are the bonds called between triglycerides?
A
ester bonds (covalent)
22
Q
which bases pair?
A
A-T
C-G
23
Q
How many H- bonds are between AT and CG
A
AT= 2 H bonds CG= 3 H bonds
24
Q
what are the functional groups of amino acids
A
COO-
H3N+-C- H
R side chain
amino group(N+H3), carboxyl group(COO-) , R side chain
25
Which part of the amino acid determines polarity or polarity
side chain
26
How many amino acids are there in total?
20
27
which group on the amino acid are positive or negative?
(amino) NH3 +
| (carboxyl) COO-
28
what joins amino acids together
peptide bonds via a condensation reaction between carboxyl and amnio groups
29
What are the primary and secondary structure of proteins
primary- linear sequence of amino acids linked by peptide bonds. dictates 3D conformation.
secondary- local folding; alpha- helix or beta pleated sheets
30
what cleaves peptide bonds?
proteolytic enzymes (proteases)
31
What are the forces that hold proteins together?
Van der Waals forces, hydrogen bonds, hydrophobic forces, ionic bonds, disulphide bridges
32
weakest force that holds proteins together?
Van der Waals
33
What are Van der Waals and hydrogen bonds?
Van der Waals- fluctuating electrical charges cause week interactive charges between molecules
Hydrogen- interaction between negative dipole on O/N/F and positive dipole on H atom (bound to O/N)
34
hydrophobic charges
uncharged/ non-polar side chains are poorly soluble in water.
hydrophobic side chains form tightly packed cores in the interior of proteins, excluding water molecules
35
ionic bonds
between fully or partially charged groups. weakened in aqueous systems by shielding by water molecules and other ions in solution
36
Disulphide bonds?
covalent bonding between side chains of cysteine
| residues
37
how does an A- helix form?
H bonds between each carbonyl group and the H attached the N which is 4 aa along the chain.
38
how does the B sheet form
H bonds between linear regions of polypeptide chains
39
What is supersecondary structure?
combination of secondary structures ( A and B)
40
Tertiary structure?
overall 3D conformation of the protein
41
forces involved in tertiary structure
electrostatic, hydrophocicity, H bonds, covalent bonds
42
quarternary structure
3D structure of a protein composed of multiple subunits
43
what factors influence the rate of chemical reaction
temperature, conc of reactants, catalysts, surface area of a solid reactant, pressure of gaseous reactants or products
44
enzymes= biological catalysts
| how do they work?
bind reactants and convert to products then release them.
| reduce the activation energy of a reaction
45
what are coenzymes
non protein, organic structures which maximise the functionality of enzyme functional groups (enzymes need them to function)
46
Which are less specific to the reaction enzymes or coenzymes
coenzymes
47
what is a porphyrin ring?
holds an iron atom in the core of haemoglobin molecule
| iron containing porphyrin= heme
48
how does a higher temperature affect hemoglobin saturation?
decreases haemoglobins affinity for oxygen and enhance oxygen unloading from the blood
49
describe prokaryotes DNA
no nuclear membrane
| DNA arranged in single chromosone
50
describe eukaryotes DNA
DNA in nucleus
bound to proteins (chromatin)
some DNA in mitochondria
51
What are the functions of DNA
Template and regulator for transcription and protein synthesis
52
what sugar is in DNA and RNA
DNA- deoxyribose
| RNA ribose
53
what bond links the 3' carbon atom of one sugar molecule and the 5' carbon atom of another
phosphodiester
54
Semi conservative replication of DNA
replicated DNA is composed of a new and old strand
55
Which way does DNA polymerase read and which way does it print
reads 3 to 5
| prints 5 to 3
56
Topoisomerase
relieves supercoil, unwinding double helix
57
DNA helicase
breaks hydrogen bonds between the two strands, exposing nucleotides
58
DNA polymerase
starts at primer and binds nucleotides to old strand of DNA after replication fork
59
What can cause DNA damage
chemicals, UV damage, radiation, chance
60
primer
short strand of DNA, acts as a starting point for DNA synthesis as DNA polymerase can only add nucleotides to an existing strand
61
what keeps the two DNA strands apart during DNA synthesis
Single strand binding protein (SSB)
62
Promotor region
transcription
| where RNA polymerase unwinds DNA double strand to reveal one strand
63
which way does RNA polymerase read and print?
read- 3 to 5
| print 5 to 3
64
what is the enzyme used in transcription to join nucleotides together along DNA template strand
RNA polymerase
65
What 3 process happen to change pre-mRNA into mature mRNA
1. splicing; introns removed, exons joined together
2. 5' cap
methylated guanine is added to 5' end so ribosomes recognise mRNA and it isn't degraded
3. poly(A) tail added to 3' end to stabalise mRNA.
66
what does the genetic code being degenerative mean?
many amino acids are coded for by more than one codon
67
universal genetic code
all organisms use the same code
68
non-overlapping genetic code
codons do not overlap
69
what initiates transcription
transcription factors bind to 5' of the 1st exon (promotor region)
70
what happens in transcription after transcription factors bind and transcription complex forms?
helix opens, dna strand seperation
| RNA polymerase starts building mRNA.
71
what factors can turn off gene expression? (stop transcription)
- activation of repressors (inhibitors of RNA polymerase)
| - RNA stability decreases
72
what is heterochromatin
heterochromatin- genes are silent as DNA inaccessible to transcription factors, due to dense genetic material and methylated DNA
73
euchromatin
unmethylated DNA so hyperaccessible chromatin (genes activable)
74
what is a primer and a promotor region
primer- piece of DNA used to start DNA synthesis
Promotor region- region of DNA (1st Exon) used for mRNA transcription
75
where does translation occur
80s ribosome
76
does a tRNA molecule have an anticodon complimentary to codon on mRNA
yes
77
what stops translation
stop codon on mRNA
78
missense mutation
DNA nucelotide is switched out for another, causing a different amino acid to be coded for
79
nonsense mutation
stop codon coded for prematurely
80
silet mutation
change in sequence of DNA nucleotides without a resulting change in the corresponding amino acids that is coded for
81
Where is DNA found within the cell
nucleus
| mitrochondria
82
what is DNA wrapped around
histones
83
what is a nucleosome
coil of DNA
| coil after coiled around histones
84
how many human chromosomes are there
46 chromosomes
| 22 pairs and sex XY
85
structure of a chromosome
q (long arm)
p (short arm)
connected by centromere
86
purpose of mitosis
two daughter cells that are genetically identical to parent cell
growth and repair
87
what happens in
G1
S
G2 phases?
```
G1= cellular contents replicated
S= chromosomes and centrosomes replicated
G2= checking duplicated genetic material
```
(then mitosis and cytokinesis happen)
88
order of mitosis
```
Prophase
prometaphase
metaphase
anaphase
telophase
```
89
prophase
chromatin condenses into chromosomes
90
prometaphase
nuclear envelope breaks down
| chromatids attach to microtubules
91
metaphase
chromsomes line up along equatorial plane
92
anaphase
sister chromatids separate and are pushed to opposite poles of the cell
93
telophase
nuclear membranes reform chromosomes reform into chromatin
94
what are the differences between meiosis to mitosis
only in gametes
creates genetic diversity
4 haploid daughter cells
2 cell divisions
95
when does crossing over occur
prophase I
96
non disjunction abnormality
failure of chromosome pairs to separate in meiosis I or sister chromatids to separate properly in meiosis II
97
numerical abnormality
chromosomal defect, different number of chromosomes
98
structural chromosomal abnormality
when parts of individual chromosome are missing, duplicated or transfered to another chromsome, or tuned upside down (insertion or translocation)
99
what is gonadal mosaicism
more than one set of genetic information is present (specifically within gamete cells)
100
when does crossing over occur
prophase I
101
what is an example of super secondary structure
Zinc finger
