2.4 proteins Flashcards

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1
Q

what is a monomer of a protein?

A

amino acid

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2
Q

draw an amino acid

A

see p. 155

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3
Q

polypeptide

A

long chains of covalently bonded amino acids joined together on the ribosome

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4
Q

how many amino acids are there?

A

20

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5
Q

peptide bond

A

a covalent bond that joins amino acids, at the carboxyl group of one amino acid to the amino group of the other amino acid, with the release of a molecule of water.

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6
Q

how can amino acids can be covalently joined together?

A

via condensation reaction, forming a dipeptide and water

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7
Q

how can polypeptide chains be broken?

A

via hydrolysis reactions

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8
Q

draw the formation of a peptide bond

A

see p. 155

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9
Q

primary structure

A
  • determines the way the chain will fold
  • Different amino acid sequences will fold into different configurations due to the chemical properties of the variable side chains
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10
Q

secondary structures (2 configurations)

A
  • folding into repeat patterns (alpha-helix or beta-pleated sheet)
  • By hydrogen bonds between amine and carboxyl groups
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11
Q

what happens if there is no secondary structure?

A

the polypeptide chain will form a random coil

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12
Q

tertiary structure

A
  • Overall three-dimensional arrangement of a polypeptide
  • Determined by interactions between variable side chains
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13
Q

quaternary structure

A

found in proteins that consist of more than one polypeptide chain linked together OR if they include inorganic prosthetic groups as part of their structure

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14
Q

An example of a protein with a quaternary structure

A

haemoglobin
- composed of four polypeptide chains (two alpha chains and two beta chains)
- It is also composed of iron-containing haeme groups (prosthetic groups responsible for binding oxygen)

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15
Q

SHITS ME

A

structure, hormones, immunity, transport, sensation, movement, enzymes

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16
Q

what is SHITS ME

A

acronym for protein functions

17
Q

collagen

A

A component of the connective tissue of animals (most abundant protein in mammals)

18
Q

spider silk (fibroin)

A

A fiber spun by spiders and used to make webs (by weight, is stronger than kevlar and steel)

19
Q

insulin

A

Protein produced by the pancreas and triggers a reduction in blood glucose levels. is a hormone.

20
Q

glucagon

A

Protein produced by the pancreas that triggers an increase in blood glucose levels

21
Q

immunoglobulins

A

Antibodies produced by plasma cells that are capable of targeting specific antigens

22
Q

haemoglobin

A

A protein found in red blood cells that is responsible for the transport of oxygen

23
Q

cytochrome

A

A group of proteins located in the mitochondria and involved in the electron transport chain

24
Q

rhodopsin

A

A pigment in the photoreceptor cells of the retina that is responsible for the detection of light

25
Q

actin

A

Thin filaments involved in the contraction of muscle fibres

26
Q

myosin

A

Thick filaments involved in the contraction of muscle fibres

27
Q

rubisco

A

(ribulose carboxylase)
the enzyme that catalyses the first step of photosynthesis (probably the most abundant protein on Earth). involved in carbon fixation during photosynthesis.

28
Q

proteome

A

The totality of all proteins that are expressed within a cell,
tissue or organism at a certain time

29
Q

why are proteome unique?

A

protein expression patterns are influenced by a unique genome

30
Q

denaturation

A

structural change in a protein that results in the loss (usually permanent) of its biological properties

31
Q

conditions that cause denaturation

A

temperature and pH

32
Q

how does temperature cause denaturation

A

High levels of thermal energy may disrupt the hydrogen bonds that hold the protein together
As these bonds are broken, the protein will begin to unfold and lose its capacity to function as intended
Temperatures at which proteins denature may vary, but most human proteins function optimally at body temperature (~37ºC)

33
Q

how does pH cause denaturation

A

alters protein charge ➡ changes solubility & shape

34
Q

albumin

A

the main protein of human plasma. Its main function is to regulate the osmotic pressure of blood.

35
Q

amino group

A

NH2

36
Q

carboxylic group

A

COOH

37
Q

gene

A

a heritable section of DNA that controls a specific trait.

38
Q

ribosome

A

cell organelle functioning as the site of protein synthesis.