Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Phase 1 > IMMS > Flashcards

IMMS Flashcards

1
Q

What is the purpose of mitosis?

A

Makes 2 genetically identical daughter cells
Growth
Replaces dead cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe prophase and metaphase

A
  • Prophase: chromatin condenses into chromosomes, centrosomes nucleate microtubles and move to opposite poles of nucleus
  • Pro metaphase: nuclear membrane breaks down, chromatids attach to microtubules
  • Metaphase: chromosomes line up at equator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe anaphase and telophase

A

After metaphase:
- Anaphase: sister chromatids separate to opposite poles

  • Telophase: nuclear membranes reform, chromosomes uncoil to chromatin, cytokinesis starts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Key points of meiosis

A
  • 4 haploid daughter cells
  • genetically different, for diversity
  • 2 cell divisions
  • only in gametes
  • crossing over in prophase 1
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe spermatozoa production

A

-Primordial germ cells undergo lots of mitoses to produce spermatogonia
-Meiosis begins at puberty
-Equal cytoplasm division, 4 gametes
-Millions constantly produced
-Takes 60-65 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe egg production

A

-Primordial germ cell undergoes 30 mitoses to form oogonia
-Oogonia enter prophase of meiosis I by 8th month of intrauterine life, suspended
-Cells enter ovulation 10-50 years later
-Cytoplasm divides unequally – 1 egg and 3 polar bodies (that apoptose)
-Meiosis I is completed at ovulation
-Meiosis II only completed if fertilisation occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does DNA coil into chromosomes?

A

-DNA winds around histones forming nucleosomes
-Nucleosomes coil into chromatin
-Chromatin coils into supercoils and chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is euchromatin?

A

Actively transcribing cellular DNA
light staining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is heterochromatin?

A

Transcripitionally inactive cellular DNA
Dense staining often adjacent to nuclear membrane
Highly condensed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the main parts of a chromosome?

A

P- short top arm
Q- long arm
Centromere- controls movement in division
Telomere- at tip, seals chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe G-banding in chromosomes

A

Treated with trypsin
Stained with Giesma DNA-binding dye
Gives light and dark bands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the clinical relevance of cell division?

A
  • Detecting chromosomal abnormalities
  • Categorising tumours as B/M
    -Grading M tumours
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is nondisjunction?

A

Failure of chromosome pairs to separate in meiosis 1 or
Failure of sister chromatids to separate in meiosis 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is gonadal mosaicism?

A

Occurs when precursor germ line cells are a mixture of two or more genetically different cell lines
One cell line is healthy, one is mutated
Increases with parent’s age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Examples of gonadal mosaicism

A

More common in autosomal dominant or x linked
Osteogenesis imperfecta
Duchenne muscular dystrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Clinical relevance of mitotic spindle (drugs)

A

Taxol
Vinca alkaloids
Spindle poles- ispinesib

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Clinical relevance of anaphase

A

Colchicine like drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Anagram for recognising rare disease

A

G - group of congenital abnormalites
E- extreme presentation of common conditions
N- neurodevelopmental disease/ early onset NG
E- extreme pathology
S- surprising lab results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are constitutional chromosomal abnormalities?

A

Present from birth
Occurs at gametogenesis
Affects all cells
Heritable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are acquired chromosomal abnormalities?

A

Changes occur during lifetime
Restricted to malignant tissue
Not heritable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are fusion genes?

A

Breakpoints occur within two genes
Hybrid gene created
Chimaeric protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is gene deregulation?

A

Juxtaposition of gene to regulating gene
Altered regulation result in increased transcription and neoplastic growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Define genotype

A

Genetic constitution of an individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Define phenotype

A

appearance of individual (physical, biochemical, physiological) which results from interaction of genotype and environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How to karyotype cell/tissue types

A

-Obtain sample and add to culture medium + PHA
-Incubate at 37 degrees for 48-72hrs
-Add colcemid + hyptonic solution
-Fix, mount on slide and stain cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Genetics of Downs

A

47, XX/XY, +21
Trisomy 21
1/700 chance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Genetics of Edwards syndrome

A

47, XX/XY, +18
Trisomy 18
1/3000 chance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Genetics of Patau

A

47, XX/XY, +13
Trisomy +13
1/5000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Examples of sex chromosome abnormalities

A

47, XXY, Klinefelter, 1/1000 male births
47, XXX, Triple X, 1/1000 female births
45, X, Turner, 1/2500

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is reciprocal translocation?

A

-Involves the breakage of at least 2 chromosomes, with fragments exchanging
-Chromosome number usually remains at 46
E.g. 46, XY, T(2:18) or Robertsonian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is FISH?

A

-Fluorescent In-Situ Hybridization
-DNA probe labelled with fluorochrom
-Hybridized and area visible with fluorescent microscope
-Used for diagnostic purposes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is a deletion?

A

-loss of 1+ nucleotides
-large deletions usually incompatible with survival
-e.g. cri du chat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Role of cytogenetics

A

-confirmation of malignancy
-classification of disease type
-prognosis
-monitoring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

About microarrays

A

-simultaneous analysis of several million targets
-short, fluorescent labelled oligonucleotides attach to microscope slides
-hybridization of target DNA detected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is array CGH?

A

-Comparative genomic hybridization
-hybridization of patient and reference DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How do multifactorial risks vary in families?

A
  • Dramatically higher in relatives
  • Degree of genetic relationship
  • Number of relatives affected
  • Severity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Characteristics of multifactorial inheritance

A
  • incidence greatest amongst relatives of patients
  • greatest risk for first degree relatives, decreases with extended family
  • more affected relatives = higher risk
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

About macromolecules

A
  • formed by simple molecules (amino acids, lipids, sugars)
  • have osmotic, optical, structural and enzymatic functions
  • heterogenous structures
    e.g. haemoglobin, DNA, glycogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Types of carbohydrates

A

Monosaccharides
Disaccharides
Polysaccharides
Oligosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

About monosaccharides

A
  • Chains of carbons, hydroxyl group and one carbonyl
  • aldose has a C1 aldehyde
  • ketose has a ketone
  • generally ring structures
    e.g. glucose, glyceraldehyde, ribose
    produced by digestion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Which glycosidic bond is found in carbs and nucleotides?

A

O-glycosidic in carbs
N-glycosidic in nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

About oligosaccharides

A
  • Between 3-12 monosaccharides
  • Products of digestion of poly/ parts of complexes
  • n- linked sugars
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

About polysaccharides

A
  • Thousands of MS with glyc bonds
  • Starch, glycogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are proteoglycans?

A
  • long, unbranched PS radiating from core protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

About fatty acids

A
  • Straight C chains with methyl and carboxyl groups at ends
  • Saturated or unsaturated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are steroids?

A
  • Cholesterol is precursor to all human steroids
  • Have a 4 ring structure called steroid nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Nucleoside structure

A

A nitrogenous base joined to a sugar through a n-glycosidic bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Nucleotide structure

A

Nucleoside + phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Which bases are purines and pyramidines?

A

Purine: A & G, 2 rings
Pyramidine: T, C, U, 1 ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What are amino acids?

A
  • Contain an amine group and a carboxylic acid group
  • Side chain (R) often determines polarity
  • Charge determined by all 3 components, can change at different pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Properties of peptide bonds

A
  • very stable
  • cleaved by proteolytic enzymes
  • partial double bond
  • flexibility around C atoms not in bond allows multiple conformations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What forces can hold proteins together?

A
  • London (when close fit)
  • H bonds (between dipoles)
  • Hydrophobic (pack in protein interior)
  • Ionic (between charged groups)
  • Disulphide (covalent between cysteine R)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Primary structure of a protein

A
  • linear sequence of aa
  • determines 3D conformation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Secondary structure of a protein

A
  • alpha helices (H bonds between aa)
  • beta sheets (pleated or not, between linear polypeptide chains, parallel if strands run in same direction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Tertiary structure of a protein

A
  • overall 3D conformation of protein
  • contains range of forces
  • can change with pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Quaternary structure of a protein

A
  • association of individual polypeptide chain subunits
  • same non-covalent interactions as tertiary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

About enzymes

A
  • biological catalysts
  • binds the substrates, brings them at right orientation for reaction, releases products and remains unchanged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

About myoglobin

A
  • globular protein composed of a single polypeptide chain with 1 O2 binding site
  • present in heart and skeletal muscle
  • can bind the O2 released from haemoglobin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

About haemoglobin

A
  • tetramer composed of two different types of subunits, 2 alpha and 2 beta polypeptide chains
  • heme consists of planar porphyrin ring, Fe in centre binds to 4 N, Fe site of O2 binding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is the immunoglobulin (antibody) structure?

A
  • 2 identical small (light) + 2 identical large (heavy) polypeptide
  • Chains joined by disulphide bonds
  • Both light and heavy regions contain variable (V) and constant (C) regions
  • V regions interact to produce single antigen binding site at each branch
  • summary: supporting scaffold to display complementarity determining regions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

How do the CDR of immunoglobulins work for binding?

A
  • Wide range of reversible bonding between antigen and antibody
  • very close proximity of antigen surface and cdr
  • CDR has AA sequence that complements antigen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is the portion of the antigen bound known as?

A

Epitope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Which bases pair and why is DNA base pairing good?

A
  • Adenine and thymine, 2 H bonds
  • Cytosine and guanine, 3 H bonds
  • Purines flip over to be in correct orientation
  • Pairing allows one strand of DNA to serve as a template for other strand and also RNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What does antiparallel mean?

A
  • The two strands of DNA run in opposite directions
  • On one strand the 5 C of the sugar is above the 3 C, so this strand runs in the 5’ to 3’ direction
  • Other, 3’ above 5’ so runs 3’ to 5’ direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is the structure of the DNA double helix?

A
  • Purine bonded to pyrimidine so equidistant
  • Stacked bases stabilised by Van der Waals and hydrophobic effects
  • Phosphate groups on outside, 3rd -OH on phosphate is free and dissociates a H+ at physiological pH, so DNA -ve charge
  • contains major and minor grooves where bases can interact with other molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Describe the process of DNA replication (S phase)

A
  1. DNA helicase disrupts binding to open into replication fork
  2. Leading strand runs 3’ to 5’, lagging is 5’ to 3’
  3. RNA primer bonds to leading at 3’ end
  4. Leading strand replicated by polymerases, continuous
  5. Lagging strand binds with multiple primers, polymerase adds DNA (okazaki fragments), discontinuous
  6. When both strands formed, exonuclease removes primers and replace with bases
  7. DNA Ligase joins lagging strand up
  8. Telomerase catalyses synthesis of new telomeres at ends
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

About DNA polymerase in DNA replication

A
  • Reads 3’ to 5’, prints 5’ to 3’
  • Deoxyribonuceloside triphosphates serve as substrates for addition of nucleotides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What is the function of DNA?

A
  • Template and regulator from transcription and protein synthesis
  • Structural basis of heredity and genetic disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Which enzymes/proteins work to open the strands of DNA?

A
  • Helicase opens it
  • Single stranded binding proteins keep it open
  • Topoisomerase unwinds supercoil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

List some forms of DNA damage

A
  • Ionising radiation: damage bases, break phosphate backbone
  • UV: Damage bases, e.g. thymine dimers
  • Spontaneous insertion of wrong bases in rep
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What is the p53 protein and what does it do?

A
  • Transcription factor that regulates cell cycle and apoptosis
  • Halts replication in cells that have suffered DNA damage
  • Loss of both p53 alleles common in tumours
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Examples of drugs used in cancer to interfere with DNA replication

A
  • Inhibitors of nucleotide synthesis: methotrexate
  • DNA polymerase inhibitors: cytosine arabinoside
  • DNA template damaging agents: cyclophosphamide
  • Inhibitors of DNA topoisomerase: doxorubicin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What is the structure of mRNA?

A
  • long linear transcript
  • 5’ CAP and Poly(A) tail
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What is the structure of a prokaryotic ribosome?

A
  • 70S split into 50S and 30S subunits
  • 50S contains 5S and 23S rRNAs
  • 30S contains 16S rRNA complexed with proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What is the structure of a eukaryotic ribosome?

A
  • 80S split into 60S and 40S subunits
  • 60S subunit contains 5S, 28S and 5.8S rRNAs complexed with proteins
  • 4OS contains 18S
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What is the structure and role of tRNA?

A
  • Carry AA to ribosomes to ensure incorporated into appropriate positions
  • Many AAs have more than one tRNA, tRNAs only have one AA for their anticodon
  • Very small, around 80 nucleotides
77
Q

Describe process of transcription + mRNA splicing

A
  1. RNA polymerase binds to transcription factor complex in promoter region
  2. Helix unwinds, synthesis of RNA transcript is initiated
  3. Elongation of RNA transcript, DNA template copied, strands rejoin as polymerase passes
  4. Reaches stop codon, RNA polymerase detaches, single strand of pre-mRNA - end of transcription
  5. mRNA splicing occurs to remove introns
  6. mRNA leaves via nuclear pore into cytoplasm
78
Q

Describe the process of translation

A
  1. Complex forms between met-tRNA, ribosome and mRNA
  2. Small ribosome subunit binds to 5’ end of mRNA, scans until reaches start codon
  3. tRNA binds to ribosome and amino acid added, peptide bonds
  4. Polypeptide chains become larger and start to fold, end of translation
79
Q

How is gene expression initiated

A
  1. Transcription factors at promoter region. Transcription complex forms at TATA box
  2. Helix opens, DNA strands separate
  3. RNA polymerase II starts building mRNA
80
Q

Roles of the RNA polymerases

A

I - produces most of the rRNAs
II- produces mRNA
III- produces small RNAs
Same mechanism, recognize different promoters

81
Q

What is chromosome 22q11 deletion syndrome?

A

DiGeorge syndrome/ Velocardiofacial syndrome
1 in 4-6,000
Congenital heart diseases -74%
Palatal abnormalities- 69%
Learning difficulties- 70-90%
Immunodeficiency- 77%
90% de novo, 10% inherited

82
Q

What is Mendelian inheritance?

A

Autosomal and sex-linked
Dominant or recessive

83
Q

What is non-Mendelian inheritance?

A

Imprinting
Mitochondrial inheritance
Multifactorial
Mosaicism

84
Q

Describe cystic fibrosis (genetics)

A

1 in 2,500
Autosomal recessive
CFTR gene on7q31.2
Over 1,000 mutations- mutational heterogeneity

85
Q

Examples of autosomal recessive diseases

A

Haemochromatosis
CF
Sickle cell
Deafness

86
Q

Describe X-linked inheritance

A

Genes carried on the X chromosome
Usually only males affected
No male to male transmission
An affected male cannot have an affected son, but can have carrier daughters

87
Q

What are mitochondrial genetic diseases?

A

Group of disorders caused by dysfunctional mitochondria
Caused by mutations in mitochondrial DNA/ nuclear genes whose products are imported into the mitochondria

88
Q

What does mRNA splicing allow?

A

If alternative splicing, different proteins can be made from the same gene
Exon shuffling allows new proteins to be made, e.g. immune system

89
Q

Types of variants in genes

A
  • Deletions: whole gene or some exons
  • Duplications of gene or parts of gene
  • Splice site variants, frameshift mutations, affects accurate removal of an intron
  • Missense: base pair sub leads to different AA
  • Nonsense: sub leads to generation of stop codon and premature end of translation
90
Q

Diseases caused by expansions of trinucleotide repeats

A

Huntington’s - CAG
Myotonic dystrophy - CTG, also example of anticipation
Fragile X - CGG

91
Q

What are loss of function variants?

A
  • Only one allele functioning
  • Most recessive
  • Haploinsufficiency
92
Q

What are gain of function variants?

A
  • Increased gene dosage
  • Increased protein activity
93
Q

What are dominant-negative variants?

A

Where the protein from the variant allele interferes with the protein from the normal allele

94
Q

When would you carry out a diagnostic test?

A

Patient has signs and symptoms suggesting condition
A molecular genetic test will confirm a diagnosis
Issues informed consent

95
Q

When would you carry out predictive testing?

A

Testing at risk family members for a previously identified familial variant

96
Q

When would you carry out carrier testing?

A

Couple testing, individua not usually helpful
Reproductive decision making
Recessive or X-linked conditions

97
Q

When would you carry out pre-natal testing?

A

Performed in pregnancy when there is an increased risk of foetus being affected
Counselling issues
CVS or amniocentesis

98
Q

What is PGD?

A

Pre-Implantation genetic diagnosis
8-cell embryo has one cell removed under gentle suction
Single cell free for analysis

99
Q

What is Sanger screening?

A

Uses PCR to amplify regions of interest followed by sequencing of products
Useful for single gene testing
High cost per gene and time consuming
Simple analysis but very accurate

100
Q

What is next generation sequencing?

A

Massively parallel sequencing
Can sequence whole genome in a day
Multi gene panels
Low cost per gene and fast
Moderately accurate
Huge amounts of data

101
Q

What does metabolism refer to?

A

The sum of chemical reactions that take place within each cell in the organism

102
Q

What are the 4 main metabolic pathways?

A

Biosynthetic- anabolic
Fuel storage- anabolic
Oxidative processes- catabolic
Waste disposal- either

103
Q

What are the uses of dietary components?

A

Body components
Fuel stores
Energy
Waste products

104
Q

What is the structure of ATP?

A

Adenine 5’-triphosphate
Adenine
Ribose
3 Phosphate groups

105
Q

Purpose of ATP to ADP

A

Reaction is energetically favourable, negative Gibbs
Hydrolysis
Energy utilization
E.g. biosynthesis, active ion transport, muscle contraction

106
Q

Purpose of ADP to ATP

A

Energy production via oxidation of carbs, lipids, proteins

107
Q

Brief description of glycolysis

A

Anaerobic breakdown of glucose to pyruvate
Small amount of ATP from substrate level phosphorylation
Occurs in cytosol

108
Q

Brief description of Krebs cycle

A

Oxidation of acetyl CoA
Coenzymes NADHand FADH2

109
Q

Brief description of oxidative phosphorylation

A

Transduction of energy derived from fuel oxidation to high energy phosphate
Generates large amounts of ATP

110
Q

What is the equation for glycolysis?

A

Glucose + 2NAD + 2 Pi + 2ADP —-> 2 Pyruvate + 2NADH + 4H + 2ATP + 2H2O

111
Q

Brief summary of the prep phase in glycolysis

A

Glucose. 2 ATP in, forms Fructose-1,6-bisphosphate

112
Q

Brief summary of the ATP generating phase of glycolysis

A

2 triose phosphates, 2NADH 2ATP 2ATP generated, 2 pyruvate

113
Q

Stages of glycolysis prep phase

A

-Glucose to (ATP to ADP, hexokinase)
-Glucose 6-phosphate to (phosphoglucose isomerase)
-Fructose 6-phosphate to (ATP to ADP, phosphofructokinase-1)
-Fructose-1,6-bisphosphate to (aldolase)
-Dihydroxyacetone phosphate or (triose phosphate isomerase) -glyceraldehyde 3-phosphate

114
Q

Stages of glycolysis ATP generating phase

A

-Glyceraldehyde 3-phosphate to (triose phosphate dehydrogenase, 2 NADH + 2 H)
-1,3-bis-phosphoglycerate to (ADP to ATP, phosphoglycerate kinase)
-3-Phosphoglycerate to (phosphoglyceromutase)
-2-Phosphoglycerate to (enolase, H2O out)
-Phosphoenol pyruvate to (ADP to ATP, pyruvate kinase)
-Pyruvate

115
Q

What is regulated in glycolysis?

A

Hexokinase
Phosphofructokinase-1
Pyruvate kinase
Dehydrogenase

116
Q

What is the rate limiting enzyme in glycolysis?

A

Phosphofructokinase-1
Controls the rate of glucose 6-phosphate into glycolysis
Allosteric enzyme with 6 binding sites

117
Q

What are allosteric activators and inhibitors?

A

Compounds that bind at sites other than the active site that regulate the enzyme through conformational changes that affect the catalytic site

118
Q

What are the two main hormonal regulators of glycolysis and how does it work?

A

Insulin: activates key glycolytic enzymes
Glucagon: inactiveates key glycolytic enzymes
Indirect
Glycolytic enzymes are sensitive to cell’s energy levels

119
Q

How is phosphofructokinase-1 regulated in glycolysis?

A

ATP: inhibits PFK1
AMP (when ATP is used up): activates PFK1 to make more ATP in glycolysis
Citrate from Krebs: inhibits PFK1 as more energy isn’t needed
Fructose 2,6-bisphosphate: activates PFK1, also mediates effects of insulin and glucagon

120
Q

Formula for glycolysis in anaerobic conditions

A

glucose + 2ADP + 2Pi → 2lactate + 2ATP + 2H2O + 2H+

121
Q

What happens to pyruvate in anaerobic conditions?

A

Lactate dehydrogenase reaction
Pyruvate reduced to lactate in cytosol, NADH required
Lactate and H+ transported out of cell into interstitial fluid and diffuse into blood
If exceeds buffering range of blood, lactate acidosis
Reversible

122
Q

What happens to pyruvate in aerobic conditions?

A

Irreversible
In mitochondrial matrix, catalysed by pyruvate dehydrogenase
pyruvate + CoA + NAD+ ——> acetyl-CoA + CO2 + NADH + H+
Inhibited by high concs of products
Inactivated by phosphorylation, activated by phosphate removal

123
Q

Brief description of Krebs/TCA

A

In mitochondrial matrix, aerobic
aka tricarboxylic acid cycle
Generates lots of ATP and intermediates for other metabolic pathways

124
Q

Overall equation for Krebs

A

acetyl-CoA + 3NAD+ + FAD + GDP + Pi + 2H2O ——> 2CO2 + 3NADH + FADH2 + GTP + 3H+ + CoA

125
Q

Describe the stages of the TCA cycle to succinyl CoA

A

-Acetyl CoA to (citrate synthase)
-Citrate to (aconitase)
-Isocitrate to (NAD+ to NADH + H+, CO2 out, isocitrate dehydrogenase)
-alpha-ketoglutarate to (NAD to NADH + H+, CO2 out, alpha-ketoglutarate dehydrogenase)
-Succinyl CoA

126
Q

Describe the stages of the TCA cycle from succinyl CoA to oxaloacetate

A

-Succinyl CoA to (GDP +Pi to GTP, succinate thiokinase)
-Succinate to (FAD TO FAD2H, succinate dehydrogenase)
-Fumarate to (fumarase)
-Malate to (NAD to NADH + H+, Malate dehydrogenase)
-Oxaloacetate to
-Acetyl CoA

127
Q

TCA
A…
C…
I…
K…
S…
S…
F…
M…
O…

A

Aceytl CoA
Citrate
Isocitrate
alpha-ketoglutarate
Succinyl CoA
Succinate
Fumarate
Malate
Oxaloacetate

128
Q

Glycolysis
G…
G…
F…
F…
D…/G…
B…
P…
P…
P…
P…

A

Glucose
Glucose 6-Phosphate
Fructose 6-Phosphate
Fructose 1,6-bisphosphate
Dihydroxyacetone phosphate/ glyceraldehyde 3-phosphate
1,3-bisphosphoglycerate
3-phosphoglycerate
2-phosphoglycerate
Phosphoenol pyruvate
Pyruvate

129
Q

Describe the regulation of enzymes in Krebs

A

Isocitrate dehydrogenase: inhibited by ATP, NADH, activated by ADP
Citrate synthase: inhibited by ATP, NADH, Citrate, activated by ADP
alpha-ketoglutarate dehydrogenase: inhibited by ATP, NADH, GTP, Succinyl CoA, activated by Ca2+

130
Q

How is pyruvate dehydrogenase regulated?

A

Inhibited by: ATP, NADH, Acetyl CoA
Activated by: ADP, pyruvate

131
Q

Brief description of oxidative phosphorylation

A

In the inner mitochondrial matrix
aerobic
NADH and FADH2 through electron transport chain
Produces O2 and ATP
Releases majority of energy during cellular respiration

132
Q

Describe the process of oxidative phosphorylatin

A
  1. NADH or FADH2 donate electrons
  2. electrons move along electron transport chain: accepted via reduction, move on (oxidation). NADH electrons move down complex I, complex III and complex IV
  3. At each of the complexes, e- transfer is accompanied by proton pumping across membrane into inter membrane space
  4. Drop in energy as electrons move down conc gradient
  5. matrix more alkaline as H+ moved out, and more -ve so protons draw back in, via ATP synthase
  6. 12 protons synthesize 3 ATP
133
Q

What is adipose tissue specialised for?

A

85% fat
Storage of energy-rich molecules

134
Q

What is liver tissue specialised for?

A

metabolically active
e.g. gluconeogenesis, removal of toxins

135
Q

What is the cori cycle?

A

Metabolic route to get rid of lactate and keep producing energy anaerobically
Lactate returns to liver and is reconverted to glucose via gluconeogenesis

136
Q

What is gluconeogenesis?

A

Formation of new glucose by the liver
Converts new non-carbohydrates to glucose, e.g. lactate, glycerol, AAs

137
Q

Functions of insulin

A

-Promotes fuel storage after a meal
-Promotes growth
-Stimulates glucose storage as glycogen
-Stimulates fatty acid synthesis and storage after a high-carb meal
-Stimulates amino acid uptake and protein synthesis

138
Q

Functions of glucagon

A

-Mobilisizes fuels
-Activates gluconeogenesis and glycogenolysis during fasting
-Activates fatty acid release from adipose tissue

139
Q

Storage of dietary fuels: fat, carbohydrate, protein

A

Fat- adipose tissue (only 15% water)
Carbohydrate- as glycogen in liver and muscles
Protein- muscle (80% water)

140
Q

What happens to excess energy intake?

A
  • store as triglycerides in adipose (15kg)
  • store as glycogen (200g in liver, 150g in muscle), 80g in the liver after overnight fast
  • store as protein in muscle (6kg)
141
Q

How much energy per gram of carb, protein, lipid, alcohol

A

Carbohydrates: 4kcal
Protein: 4kcal
Alcohol: 7kcal
Lipid: 9kcal

142
Q

What is BMR?

A

A measure of energy needed to maintain non-exercise bodily functions

143
Q

List examples of non-exercise bodily functions for BMR

A

-Respiration
-contraction of the heart muscle
-biosynthetic processes
-repairing and regenerating tissues
-ion gradients across cell membranes

144
Q

What are the conditions for measuring BMR?

A
  • 12hour fast
  • lying still at rest
  • 27-29 degrees environment
  • no tea, coffee, nicotine, alcohol in previous 12 hours
  • no heavy physical activity previous day
  • establish steady state for 30 minutes
145
Q

Factors decreasing BMR

A

Age
Males lower than females
Dieting/ starvation
Hypothyroidism
Decreased muscle mass

146
Q

Factors increasing BMR

A

Higher BMI
Hyperthyroidism
Low ambient temp
Fever/infection/chronic disease

147
Q

What happens if starvation occurs for 2-4 days?

A

insulin drops, cortisol rises
gluconeogenesis

148
Q

What happens if starvation occurs for more than 4 days?

A

Liver makes ketones from fatty acids
Brain adapts to using ketones
BMR decreases

149
Q

What is re-feeding syndrome?

A

Potentially fatal condition
Severe electrolyte and fluid shifts as a result of a rapid reintroduction of nutrition after a period of inadequate nutritional intake

150
Q

Function of vitamin C (ascorbic acid)

A
  • collagen synthesis
  • improve iron absorption
  • antioxidant
151
Q

Function of vitamin B12

A
  • protein synthesis
  • DNA synthesis
  • regenerate folate
  • fatty acid synthesis
  • energy production
152
Q

Function of vitamin B1

A
  • B1 (thiamine): break down and release energy from food, keep NS healthy
153
Q

Function of folate

A

-Helps to produce and maintain DNA and cells
-Helps make enough RBCs
-Enough folic acid reduces risk of baby having birth defects

154
Q

Function of vitamin A

A
  • Helps vision in dim light
  • Helps natural defence against infection
  • Promotes normal growth and development
  • Keeps skin healthy
155
Q

Function of vitamin D

A
  • increases amount of calcium and phosphorus your body absorbs from food
  • deposits calcium and phosphorus in bones and teeth to keep them strong and healthy
156
Q

Function of vitamin E

A
  • Helps maintain a healthy immune system and other body processes
  • Acts as an antioxidant and protects cells from damage
157
Q

Function of vitamin K

A
  • Makes proteins that cause our blood to clot
  • Involved in making body proteins for blood, bones and kidneys
158
Q

Features of a prudent diet

A

-5 a day
-5% max energy from free sugars
-0.8g/kg/day protein
-no more than 20g (women) 30g (men) saturated fat a day
-no more than 2.4g sodium (6g salt) a day
-avoid excess dietary supplementation
-adequate calcium
- no more than 14 units alcohol a week

159
Q

Function of vitamin B2

A

(riboflavin): energy production from food

160
Q

Function of vitamin B3

A

B3 (niacin): helps body to use fat, carbs and protein for energy, helps enzymes work

161
Q

Function of vitamin B6

A

B6 (pyridoxin): helps make and use protein and glycogen, helps form haemoglobin

162
Q

Function of vitamin B7

A

B7 (biotin): in small amounts, allows body to use protein fat and carbs from food, make fatty acid

163
Q

What are the stages of lipid absorption and transport?

A
  1. Bile salts emulsify dietary fats in the small intestine, forming mixed micelles
  2. Intestinal lipases degrade triacylglycerols
  3. Fatty acids and other breakdown products are absorbed by intestinal mucosa, bile salts left and resorbed
  4. FAs converted into triacylglycerols, then incorporated with cholesterol and apoproteins to form chylomicrons
  5. Move through lymphatic and bloodstream to tissues
  6. Lipoprotein lipase releases FAs and glycerol
  7. FAs enter cells
164
Q

Describe process of fatty acid activation

A

Pre-oxidation
Acyl-CoA synthetase + energy from ATP
FA —-> fatty acyl AMP intermediate and pyrophosphate (PPi)
PPi cleaved to drive reaction forming fatty acyl CoA

If acyl-CoA has less than 12C, it diffuses through mitochondrial membrane
12-14C are taken through mitochondria via carnitine shuttle

165
Q

Describe process of FA β-oxidation

A

Fatty acyl CoA ——> acetyl CoA for Krebs
1. Acyl CoA to (FAD to FADH2, acyl CoA dehyrdogenase)
2. trans fatty enoyl CoA to (H2O in, enoyl CoA hydratase)
3. L-β-Hydroxy acyl CoA to ( NAD+ to NADH + H+, β-hydroxy acyl CoA dehydrogenase)
4. β-keto acyl CoA to (CoASH in, β-keto thiolase)
5. Acetyl CoA

166
Q

Basic stages of reaction types in FA β-oxidation

A
  1. Oxidation
  2. Hydration
  3. Oxidation
  4. Thiolysis
167
Q

Where does acetyl-CoA go after FA oxidation?

A

Most goes to TCA cycle
Some converted into ketones
An excess leads to ketogenesis

168
Q

What is ketogenesis?

A

Metabolic pathway that produces ketone bodies

169
Q

What makes up the lipid bilayer?

A

Intergral proteins
Peripheral proteins
Glycolipids
Glycoproteins
Cholesterol to aid fluidity
Phosolipids

170
Q

Describe channel proteins

A

Integral, span both layers
Selective (size, charge etc…)
Passive
May be gated

171
Q

What is role of carrier proteins?

A

Transport large protein molecules

172
Q

What are the different types of carrier protein and their roles?

A

Uniport – single substance
Symport – two substances in the same direction
Antiport – two substances in the opposite direction

173
Q

Features of a carrier protein

A

Specific binding site
Carrier undergoes a conformational change
Active pumps or passive

174
Q

How does a chemical driving force across a membrane work?

A

Based on concentration differences across the membrane
All substances have a concentration gradient
Force directly proportional to the concentration gradient

175
Q

How does an electrical driving force work across a membrane?

A

Also known as membrane potential
Based on the distribution of charges across the membrane
Only charged substances e.g. Na+, K+
Force depends on size of membrane potential and charge of the ion

176
Q

How does an electrochemical driving force work across a membrane?

A

Combines the chemical and electrical forces
Net direction is equal to the sum of chemical and electrical forces
Only charged substances e.g. Na+, K+

177
Q

How does passive transport work?

A

Does not require an input of energy
Substance moves down its gradient (high to low)

178
Q

What are the 2 types of passive transport?

A

Simple diffusion e.g. gases
Facilitated diffusion - mediated by proteins (channel or carrier)

179
Q

How is glucose taken up across a membrane?

A

GLUT4 carrier protein:
Expressed in skeletal muscle and adipose tissue
Glucose uptake by facilitated diffusion
Expression upregulated by insulin

180
Q

What is GLUT1 and its deficiency?

A

GLUT1 present in many cells, including the brain, where it transports glucose across the blood-brain barrier via facilitative diffusion
GLUT1 Deficiency Syndrome:
- Very rare disorder
- Mutations in gene that encodes GLUT1
- Less functional GLUT1 - reduces the amount of glucose available to brain cells
- Symptoms include seizures, microcephaly, developmental delay

181
Q

How does active transport work?

A

Requires an input of energy
Substance moves against its gradient (low to high)

182
Q

What is primary active transport?

A

Directly uses a source of energy, commonly ATP
Common example is Na+/K+-ATPase:
- Pumps 3 Na+ out of the cell, 2 K+ into the cell
- Utilises the hydrolysis of ATP to ADP + Pi

183
Q

What is secondary active transport?

A

Transport of a substance against its gradient coupled to the transport of an ion (usually Na+ or H+), which moves down its gradient
Uses energy from the generation of the ions electrochemical gradient (usually by primary active transport)
Example is the Na+/glucose cotransporter proteins (SGLT)

184
Q

What do proteins in SGLT1 do?

A

Present in intestinal lumen and renal tubules
Transports glucose from low to high concentration
Na+/K+-ATPase generates a sodium gradient to enable co-transport of sodium and glucose

185
Q

What is glucose-galactose malabsorption?

A

Very rare disorder
Mutations in SGLT1
Less functional SGLT1 -inability to transport glucose and galactose, resulting in their malabsorption
Symptoms include severe, chronic diarrhoea, dehydration, failure to thrive

186
Q

What is cell signalling?

A
  • Communication between cells takes place via signalling molecules e.g. hormones, neurotransmitters and growth factors
  • Signalling molecules bind to receptors:
  • Intracellular – e.g. steroid hormones
  • Cell-surface – e.g. peptide hormones
  • Second messengers (cAMP, IP3, DAG, Ca2+) - amplification
  • Affect gene expression in the nucleus either directly or through signalling cascades
187
Q

What is endocytosis?

A

Allow larger molecules that cannot diffuse through the lipid bilayer to cross the membrane
Foreign material is engulfed within the cell membrane, which then forms a vesicle containing the ingested material

188
Q

What are the subtypes of endocytosis?

A

Phagocytosis- immune purposes e.g. bacteria
Pincytosis – non-specific uptake of fluid surrounding the cell, allowing it to take in nutrients such as ions, enzymes and hormones
Receptor-mediated endocytosis – uptake of specific target substances, such as iron, via their receptor

189
Q

What is exocytosis and how does it work?

A

Form of active transport through which large molecules are moved from the interior to the exterior of the cell
Vesicles are packaged within the cell and transported to the cell membrane, where their phospholipid bilayers fuse
Contents released outside the cell

Phase 1 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions