Biochemistry Flashcards
1
Q
Functions of the citric acid cycle
A
- Common metabolic pathway for all “fuel” molecules
- fields energy that is passed to the etc which produces large amounts of ATP
- it is efficient as it is cyclical and can make a lot of NADH + FADH2
2
Q
Where does the Krebs cycle occur?
A
- In the mitochondrial matrix
3
Q
How is acetylcoA made
A
From pyruvate through action of enzyme private dehydrogenase
4
Q
Can I keep selling sex for money officer?
A
Citrate
Isocitrate
A-ketoglutarate
Succinyl coA
Succinate
Fumarase
Malate
Oxoaloacetate
5
Q
Function of glycogen in skeletal muscle and liver
A
- 90% in liver + skeletal muscle:
~ liver: acts to replenish blood glucose when fasting
~ skeletal muscle: catabolism produces ATP for contraction
6
Q
What reactions in the citric cycle involve electron carriers?
A
7
Q
What steps involve the release of coz?
A
Oxidative decarboxylation
8
Q
What are the classes of amino acids?
A
- Aliphatic amino acids: ‘R’ group consists of hydrocarbon chains
- aromatic amino acids: ‘R’ group consisting of hydrocarbon ring
- Sulphur-containing amino acids: can make disulfide bridges to increase strength
- basic amino acids
- acidic amino acids: COO
- polar amino acids: CH2OH
- A miscellaneous amino Acid
9
Q
Function of proteins
A
- amino acids arranged in a particular structure that enables it to carry out a specific function in a particular context
-Structural: acts as a ‘scaffold’
- functional: e.g. Enzymes/antibodies
10
Q
Primary structure of proteins
A
- Sequence of amino acid monomers bonded to form a polypeptide chain
11
Q
Name for multiple monomers joined together
A
- 2: dipeptide
- 3: tripeptide
12
Q
Secondary structure of proteins
A
- The 3D spatial arrangement of amino acids, relies on hydrogen bonding between the amino acid hydrogen + carbonyl group of another amino acid in the chain
13
Q
Tertiary structure of proteins
A
- The ‘p’ chains of amino aceas in polypeptide chains interact with one another
- Van der Walls, ionic, hydrogen, disulphide + hydrophobic interactions
14
Q
Quaternary structure of proteins
A
- Several polypeptides interacting to form a highly folded structure
15
Q
What are the functions of proteins:
A
- Structural
- enzymatic
- receptor
- hormonal
- Transport
- storage
- defensive
- contractile
16
Q
What properties would quaternary structure confer?
A
- Glycoproteins
- Lipoproteins
- Metalloproteins
17
Q
What are glycoproteins and what effect do they have?
A
- Proteins with >1 carbohydrate molecule covalently attached
1. Stability
2. Solubility
3. Cell signalling
4. Orientation
18
Q
Lipoproteins
A
- Proteins combine with lipids to form lipoproteins
- found in cell membrane to transport hydrophobic molecules
19
Q
Function of metalloproteins
A
- Protein molecule with metal ions in their structure
- various functions: enzymatic, signal transduction,
20
Q
Globular vs fibrous proteins
A
- Globular: storage, enzymes, hormones, transporters, structural
- fibrous: muscle fibres t connective tissue
21
Q
How do enzymes lower activation energy?
A
- Entropy reduction: orientate substrates in high ‘ direction so they bind and allow reaction to proceed,
- desolation: weak bonds are replaced by by dragon bonds between substrate + aqueous solution
- induced fit
22
Q
Ways reaction would vary if there was a change in concentration of enzyme or substrate
A
23
Q
What is the michaelis-menton plot + equation?
A
- Assess how well a reaction is going (see notes)
24
Q
What does Km tell us?
A
- A low valve = good fit
A high value = poor fit (takes a lot of substrate to get to 1/2 max
25
What does V max tell us
- How fast the reaction is proceeding when the enzyme is saturated with substrate.
26
Competitive inhibition
- Inhibitor binds to active site
- vmax is unchanged
- km increases because it takes more substrate to overcome inhibition
27
Non competitive
- Binds to secondary site & change shape of active site
- V max decreased
- km remains
28
Why are enzymes measured in a clinical setting?
- Detection of suspected disease at pre-clinical stage
- confirmation of suspected disease and assessing severity
- detecting of vitamin diseases etc.
29
What factors can influence enzyme activity in a samples?
- Age '
-Gender
- pregnancy
- Drugs
- time of day
- genetics
- race
30
How is the release of enzymes from cells triggered?
- Hypoxia: loss of oxygen supply
- cellular damage: chemicals/ drugs
- physical damage
- immune disorder
- genetic defeats
- microbiological agents: bacteria, virus, forgi
- nutritional disorders
31
What are the tissue sources of serum enzymes?
- Heart muscle; AST, LDH, ck -mb
- liver/biliary track: AST, alt, got, alp
Finish
32
What are the main nitrogen containing molecules in the body?
Dietary Protein Camino acids, RNA +dwa)
33
What is the fate of dietary protein?
- enzymatically hydrolysed:
- pepsin cuts protein into peptides in the stomach
- trypsin and chymotrypsin cut proteins and larger peptides into smaller peptides in the small intestine
- aminopeptides and carboxypeptides A and B degrade proteins into amino acids in the small intestine
34
What is the role of glutamine in the + transfer of nitrogen, from and between amino acids?
Glutamate is the only amino- acid that can obtain its nitrogen directly from ammonium ions. Nitrogen from turned-over body protein is transported through plasma to liver as glutamine, or, from skeletal muscle, as alanine.
35
Catabolism of dietary protein
1. HC1 denatures protein in stomach
2. Pepsin breaks it into ogliopepticle chains
3.in the duodenum - digestive enzymes break into tri/di peptide and amino acids
4.in the intestinal cells they all break down into amino acids
5. Some stay but others go into bloodstream to different locations
36
PKU
- Cannot convert phenyculaline to tyrosine
Brain impairment
37
Formation of urea
- Since ammonia (produced by krebscycle) is toxic it is converted to urea so we can excrete it softly
-In mitochondria: carbon dioxide and ammonium produces carbonyl phosphate
- In cytoplasm:ornithine + carbonyl phosphate = citruline
- citruline combines with aspartate = argino- succinate
- argino-succinASE acts on argino- succinate= arginine and (fumarate)
- arginate acts on arginine = UREA and ornithine (cycle begins again)
38
Examples of metabolic defects in the urea cycycle give rise to clinical defects
- Ornithine transcarbomylase (OTC) deficiency
(Elevated blood amonia) (hyper ammonaemia)
39
Types of enzymes (6)
Oxidorecductases: removes electrons
Transferases: group transfer
Lysases: transfer groups to carbon to carbon double bonds
Hydrolases: hydrolysis
Ligases: form carbon to carbon single bonds
Isomers: transfer groups to make isomers
