Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Body Cells And Structure > Structure And Function Of Proteins > Flashcards

Structure And Function Of Proteins Flashcards

1
Q

What do proteins do?

- brief explanation

A

They come in many shapes and sizes that have a variety of functions such as catalysis, defence, transport, motion, regulation and storage

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

Enzyme catalysis

- class, example and example of use

A

Class: enzymes
Examples: glucosidase, proteases, polymerises and kinases
Example of use: cleave polysaccharides, protein breakdown, synth nuclei acids and phospho prots

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

Defense

- class, example and example of use

A

Class: Ig, toxins, antigens
Example: MHC, antibodies and snake venom
Use: mark non-self for elim, block nerve function and self recog

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

Transport

- class, example and use

A

Circulating transporters: haem/myoglobin and cytochromes
Movement of O2 and CO2 in muscles and blood and movement of electrons
Membrane transporters: Na/K pump, proton pump and glucose transporter
Membrane potential, chemiosmosis and gluc transport

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

Support

- class, example and use

A

Fibres:
Collagen, keratin and fibrin
Forms cartilage, forms hair and nails and form blood clots

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

Motion:

- class, example and use

A

Muscles:
Actin and myosin
Contract muscle fibres

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

Regulation:

- class, example and use

A 
Osmotic proteins:
- serum albumin
- maintains osmotic conc of blood
Gene regulators: 
- Iac repressor 
- regs transcrip
Hormones:
- insulin, vasopressin, oxytocin
- control blood gluc, water retention and reg uterine contract and milk prod
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Storage:

- class, example and use

A

Ion-binding:

  • ferritin, casein, calmodulin
  • store iron in spleen, store ions in milk and binds Ca
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ways to classify proteins

A

Size: port or pep
Class: fibrous or globular
Role: structural or functional
Location: intra/extracellular, soluble and membranal

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

Structural proteins

A

Such as actin/intermediate filaments of cytoskeleton

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

Intracellular vs extracellular

A

Intra: targeted to a specific organelle
Extra: lumen of RER

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

Integral vs peripheral

A

Integral proteins are within the membrane

Peripheral proteins are beneath the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are proteins made of?

A

Monomers such as amino acids
Polymers such as polypeptides
Cellular structure such as intermediate/actin filaments

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

The central dogma of molecular biology

A

DNA to RNA to polypeptide to functional protein (involving folding into 3D structure with chemical modification)

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

How can such a variety of shapes and functions arise from a string of amino acids?

A

Structure gives shape to key parts of amino acids, in specific position to aid in their function

  • to interact/bind with non-prot molecules or other proteins
  • taking part in chem reactions such as catalysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Traditional enzyme characteristics

A

Enzyme contains an active site that is specific to the substrate, when it bind it become the enzyme-substrate complex (active site molded by 1/2/3 structure)

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

How many different amino acids exist

A 
20 different types: 
NON AROMATIC
-non polar: alanine, glycine (valine, isoleucine and leucine)
-polar uncharged: serine, asparagine, glutamine (threonine)
-charged: glutamic acid, arginine, aspartic acid (lysine)
AROMATIC
-non polar: (phenylalanine, tryptophan)
-polar uncharged: (tyrosine)
-charges: (histidine)
SPECIAL FUNCTION
-non polar: (proline, methionine)
-polar uncharged: (cysteine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The amino acid structure

A

N-C-C

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

Forming a polypeptide

A

2 amino acid come together forming a dipeptide via creating a peptide bind, releasing water
Formed during translation
Polypeptide has an amino end (NH3) and carboxyl end (COOH)

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

Primary structure

A

One letter code, a culmination of many amino acids in a line such as S=Serine

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

Protein translation

A

The protein will start to fold whilst it is still being translated

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

First stage of folding

A

Nearby amino acids start to form regions of stable structure such as alpha-helix or beta-sheets
Amino acids form bonds that create the specific structures
Examples: bacterial porin (all beta) and ferritin (all alpha)

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

Alpha helix importance

A

Especially important in the structure of integrate membrane proteins

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

How does the polypeptide chain rapidly fold into a compact shape

A

This is done via hydrophobic exclusions, that pushes the hydrophobic amino acids into the middle of the protein and the hydrophilic amino acids into the outer protein, this starts to form the tertiary structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Tertiary structure bonds
``` Hydrogen bonds (O-H) weak Disulphide bonds (S-S) strong, between 2 cysteines Ionic bonds (+ve with -ve) strong van see Waals (electron clouds) weak maximise contact of atoms Hydrophobic exclusions (phobic inside and phillic outside) This turns into the quaternary structure ```
26
Quaternary structure
A dimer A tetramer 2 alpha and 2 beta globins such as haemoglobin Globular and fibrous
27
Protein structure is hierarchical
Primary: structure is the protein sequence; the order of the amino acids from the N-term to the C-term Secondary: structure describes the local structure of stresses of protein: alpha-helixes or beta-sheets Tertiary: structure describes the relative positioning in the 3 dimensions of the secondary elements of a single molecule Quaternary: structure describes proteins that contain more than one chain
28
Protein degradation
Proteins can degrade via denaturation leading to a denature protein by breaking the secondary structure losing the 3D shape
29
Anfinsen experiment
Native ribonuclease contains disulphides bonds these are then reduced forming reduced ribonuclease, with the addition of heat the protein will lose its structure, this can also be reversed by cooling and oxidising the disulphide bonds back to their original formation
30
Chaperone protein | - function
They allow the repairing of midfielder protein forming the correctly folded protein Chaperone protein: GroE
31
Degrad of proteins
Aging: degrad over time as they are chemically altered | Half-life: variable between proteins
32
Size of proteins
Describes in kDa or amino acid length Is it a protein or a peptide A peptide tends to be used for very small proteins (>50 aas)
33
Fibrous or Globular
Usually describes as structural or functional Functional proteins: instigate biochem change Structural proteins: inside the cell such as the cytoskeleton or cell mem
34
Location of proteins | - intracell vs extracell
Have key difference on their biochem Extra cell prots: have to function without an energy supply, are extra tough and have disulphide bonds (structural support) mainly glycoproteins Intra cell prots: have to be located to a specific organelle
35
Soluble or membrane
Free proteins or those attaches to membrane by some mean | Membrane-bound are strongly bound and difficult to isolate and study
36
Protein denaturation
By high temperature, changes in pH and certain chemicals
37
Amino acid monomer structure
Amino group, carboxyl group and alpha carbon with side chain
38
Peptide bonds
Broken down by proteases, high temperature and pH
39
Entropy for hydrophobic exclusions
Consequence of water molecules wanting to remove themselves from the vicinity of the hydrophobic amino acids and the latter being forced into the close contact with each other
40
Primary structure dictates 3D structure
One consequence of denaturation is that the protein becomes insoluble (individual proteins can’t be insoluble) individual mis-folded protein molecules bind to each other on a process called aggregation forming an insoluble lump of protein
41
Lysosomes
Proteins are taken to them to be degraded by proteases broken down into amino acid monomers
42
Prosthetic groups
Conjugated to proteins, inorganic such as Fe, Zn and Ca Organic such as pyridoxal phosphate Porphyrin ring: the haem group of haemoglobin, contains Fe
43
Motifs and Domains
Immunoglobulins: Fab domain, Fc domain and the antigen-binding site Domains can be structural or functional Motifs such as helix-turn-helix and beta-alpha-beta, a combination of motifs are called folds
44
Hydrolysis is peptide bond
Produces amino acids Does not need energy input Proteases speed the process up Endoproteases can cleave polypeptide chain (from end of the chain)
45
Dietary supply: | - amino acids
Begins in stomach via pepsin | Completed in intestine (trypsin, chymotrypsin in duo)
46
Degrad of tissue protein: | - amino acid source
Normal turnover rate of proteins 2 methods: ubiquitin-proteasome pathway; abnorm prots on the cell cytosine (26S protease complex), gagged by ubiquitin, and ATP-depend step Lysosomal pathway; long-lived proteins in the lysosomes Degraded by proteases called cathepsins (broad spec and ATP-independ) Enter lysosomes by endocytosis, and autophagy.
47
Fate of amino acids
Synth of prots: DNA, RNA and ribosomes Synth other compounds: purines, pyrimidines and NuTs Remainder: provide energy/energy stores, no amino acid storage and they mainly stay in the liver or muscles
48
Excess protein
Protein’s amino group is removed to form ammonia, and is converted to urea leaving the carbon skeleton (alpha-ketoacid)
49
Urea cycle: | - stages
Transamination: amino acid + alpha ketoglitarate reversibly forms glutamate + alpha-keto acid Require co-factor of pyridoxal phosphate (derived from vit B6)
50
AST and ALT
Aspartate transaminase: forms aspartate from glutamate (liver) Alanine transaminase: many amino acids and muscle prots are transaminated to alanine for transport to the liver, then is further converted to glutamate
51
Nitrogen disposal: | - routes of disposal
Oxi deamination: prod NH4 - direct removal of the amino group to form ammonia, catalysed by glutamate dehydrogenase (GluDH) Glutamate —> alpha ketoglutarate Ammonia enters the urea cycle, and a-ketonwill be transaminated Transamination to aspartate: - formation of aspartate form glutamate - aspartate enters urea cycle and a-Leto same as above
52
Nitrogen disposal: - urea characteristics - urea cycle
Small, uncharged and highly water soluble (easily diffuse) and little energy requirement 1. Urea + arginine + water = ornithine + urea 2. ornithine + carbamoyl phosphate from the mito matrix (ammonia prod in mito) 3. Citrulline + aspartate + 2ATP = Argininosucciate 4. Argininosucciate loses fumarate prods arginine Overall reaction: aspartate + NH4 + CO2 + H2O + 4ATP reversibly forming urea + fumarate + 4ADP
53
Fate of urea
Transferred in blood to kidneys, can regen oxaloacetate via Malays in the cytosine using AST reaction (Malate dehydrogenase reaction), generating a net 1.5 ATP
54
Amino acid synthesis: | - process
1. Starts with a C skeleton from central metabolism 2. Use transamination reaction to add amino group 3. Further step to final amino acid structure
55
Essential amino acids
Lysine, methionine, threonine, valine, leucine, leucine, isoleucine, phenylalanine, tryptophan and histidine
56
Purine and pyrimidines
Purine: adenine and guanine Pyrimidines: cytosine, uracil and thymine
57
Amino acids are precious ones for important biomolecules
Histidine to histamine Tyrosine forming hormones such as thyroxine, adrenaline, melanin and dopamine Tryptophan: serotonin Arginine: nitric acid Serine: phospholipids Glycine: creative, bile salts and porphyrins
58
Amino acids feed into the TCA cycle
Added into each step of the cycle
59
Metabolically classifies into 2 classes: | - glucogenic and ketogenic
Glucogenic: TCA cycle intermediate are gen and used for ATP or converted to glucose Ketogenic: acetyl CoA gen to be converted to ATP or triglycerides for storage in adipose tissue (ketone bodies fuel)
60
Energy metabolism in muscle cells: - overview - excess protein - high exercise
Excess protein: - excess not stored, broken down for ATP generation or storages as glycogen or triglycerides (formation to amino acids via ALT) - muscle cells take up branches chain amino acids from the blood and use carbon skeleton for fuel/storage (BCAA aminotransferase) High intensity exercise: - rate of cycling between ATP to ADP - using creatine P used to replenish ATP

Body Cells And Structure (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions