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Biology test 1 > lecture 6 > Flashcards

lecture 6 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what are proteins made up of?

A

proteins are made up of alpha amino acid monomers that are linked to peptide bonds

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2
Q

what is the polymer of protein?

A

dipeptides and polypeptides with three or more amino acids linked together by peptide bonds

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3
Q

what determines the functions of proteins?

A

the shape and amino acid sequence

proteins are in almost every cellular function

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4
Q

what is the monomer of proteins?

A

amino acids

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5
Q

what is the structure of amino acids?

A

alpha carbon attached to an amino group and a carboxyl group

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6
Q

what types of forms can amino acids occur in?

A

a,b,y forms

alpha, beta, y=third carbon

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7
Q

what is GABA?

A

gamma-aminobutyric acid

y-amino acid that functions as a neurotransmitter that is responsible for neuron firing ( helps you relax )

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8
Q

What are D and L isomers of amino acids?

A

enantiomers

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9
Q

which isomers ( D or L ) of amino acids is used as building blocks of proteins?

A

L isomers

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10
Q

True or false

Amino acids are great biological buffers?

A

true
-they maintain the pH range of cells

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11
Q

what do amino acids do at a low pH?

A

the carboxyl and amino group accept a proton and becomes protonated

-NH3+

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12
Q

what do amino acids do at a high pH?

A

the carboxyl and amino group donates a proton and becomes dissociated

-COO-

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13
Q

what are zwitterions?

A

the term for when amino acids are present in their dipolar ionic state

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14
Q

what do the chemical and physical properties of the R group in amino acids do?

A

it determines the unique characteristics of a particular amino acid.

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15
Q

Are the R groups polar or non polar?

A

non polar

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16
Q

Are the R groups polar/electrically charged or non polar?

A

polar/electrically charged

look for positive charge (+) or look for carboxyl or hydroxyl

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17
Q

the structural and functional diversity of proteins is based on what?

A

based on the different arrangements of amino acids.

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18
Q

proteins predominantly made of leucine would be hydrophobic or hydrophilic?

A

hydrophobic ( non polar )

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19
Q

proteins predominantly made of Serine would be hydrophobic or hydrophilic?

A

hydrophilic ( polar )

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20
Q

what is the polypeptide backbone of proteins?

A

the repeating structure of atoms with side chains coming out like charms on a bracelet

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21
Q

what is the N-terminus of polypeptides?

A

the free amino end

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22
Q

what is the C-terminus of polypeptides?

A

the free carboxyl end

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23
Q

where does the energy go when forming a bond and when a breaking a bond?

A

forming a bond= energy in
breaking a bond = energy out

24
Q

what are the four levels of protein structure?

A

1) primary structure: amino acid sequence
2) secondary structure: coiling and folding in the polypeptide chain
3) tertiary structure: overall 3D shape that is determined by the amino acid side chains
4) Quaternary structure: association of multiple polypeptide chains

25
Q

In the primary structure, what determines the sequence of the amino acid chain?

A

the nucleotide sequence of the gene that encodes the protein

26
Q

what are these bonds called?

A

peptide bonds

27
Q

what occurs in sickle-cell anemia?

A

the negatively charged amino acid is replaced by a nonpolar one resulting in altered protein folding ( affecting the secondary and tertiary structure of protein ) -> this occurs in the primary structure

28
Q

what are the two types of forms created during the secondary structure of proteins?

A

1) alpha helix ( coiled - holds helix cells in shape)
2) Beta pleated sheet ( folded - hold neighboring strands of sheet together )

alpha helix = fibrous proteins of wool, skin, nails
beta pleated sheet = globular proteins, fibroin, silk protein produced by spiders

29
Q

at which level of protein stucture is the protein given its final shape?

A

tertiary stucture= given a 3D shape of the folded polypeptide chain

30
Q

what are the four possible interactions in the tertiary structure?

A

1) hydrogen bonds
2) hydrophobic interactions
3) disulfide bridges
4) ionic bonds

31
Q

what are the two forms of tertiary structure?

A

1) globular ( combinations of a-helices and b-sheets, roughly spherical)
2) Fibrous ( consisting of a-helices )

32
Q

what is hemoglobin?

A

a globular protein with four polypeptide subunits in the quaternary structure.

33
Q

what is collagen?

A

a fibrous protein consisting of three helical polypeptides coiled together

34
Q

what is protein folding?

A

when a cell synthesizes polypeptides they must fold into their correct shape or conformation

35
Q

what are chaperonins?

A

protein complexes which separate new polypeptides from the potentiallly disruptive chemical conditions within the cytoplasm.

36
Q

what are monomeric proteins?

A

proteins made of single polypeptide chain (no quaternary structure )

37
Q

what are oligomeric proteins?

A

proteins that consist of two or more polypeptide chains

38
Q

what is a conjugated protein?

A

protein that contains amino acids and some other chemical group, a prosthetic group

39
Q

what is a simple protein?

A

a protein only made up of amino acids

doesn’t combine with other macromolecules

40
Q

what is protein denaturation?

A

the process by which involves the disruption and possible destruction of both the secondary and tertiary and sometimes quaternary structures.

causes the coilage of a random shape

41
Q

what can cause protein denaturation?

A
  • heat ( frying an egg, boiling milk )
  • alcohol ( causes H-bonds to form between the new alcohol molecule and the protein side chains instead of normal H-bonds)
  • change in pH
42
Q

Give an example of denaturation in disease.

A
  • mutations
  • Alzheimer’s diease -AD (presence of protein plaques and neurofilbrillary tangles in the brain)
  • cancer ( caused by misfolding of proteins that function as tumor-suppressor agents )
43
Q

what are prions?

A

misfolded proteins that become an infectious agent
- can affect the structure of the brain or neural tissue causing untreatable fatal damage

44
Q

Why is prion dieases collectively called spongiform encephalopathies?

A

because they cause sponge-like vacuoles in the brain.

i.e. mad cow disease

45
Q

what are the two forms that prions exist as?

A

1) version consisting of three alpha helical regions and two short beta sheets
2) misfolded form made of beta sheets (infectious agent)

46
Q

what is happening in this image?

A

Prion proteins are attaching to normal proteins and infecting them causing them to become a prion and affect other prions.

47
Q

what are the 8 protein functions?

A

1) enzymatic proteins
2) storage proteins
3) chemical messenger proteins
4) contractile and motor proteins
5) defensive proteins
6) transport proteins
7) receptor proteins
8) structural proteins

48
Q

what is the role of enzymatic proteins?

A

function is to accelerate chemical reactions

49
Q

what is the role of storage proteins?

A

function is to provide a source of amino acids for developing embryos or developinh infants (milk)

50
Q

what is the role of chemical messengers?

A

its role is to coordinate an organism’s activities such as hormones ( endocrine system ) and neurotransmitters ( nervous system )

ex: insulin , acetylcholine ( ACh)

51
Q

what is the role of contractile proteins?

A

function in movement

muscle movement, undulations of cilia and flagella

52
Q

what is the role of defensive proteins?

A

function as defensive substances within the body

parasite, bacteria, virus

53
Q

what is the role of transport proteins?

A

function is to move substances within the body or in and out of cells

hemoglobin

54
Q

what is the role of receptor proteins?

A

function is to regulate the response of the cell to chemical stimuli

55
Q

what is the role of structural proteins?

A

function is to provide support. They function in the cell membrane, muscle tissue, tendons and ligaments

collagen and elastin = fibrous proteins

Biology test 1 (8 decks)

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