Protein & DNA Flashcards

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1
Q

what provides most of the molecular functions of life?

A

proteins

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2
Q

what is a protein / another name for a protein?

A

a string (polymer) of amino acids / polypeptide

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3
Q

amino acid structure

A

central alpha carbon

amino group NH2

carboxyl group CO2H

hydrogen atom

side chain “R” group

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4
Q

how many “R” groups are there?

A

20 – different amino acids

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5
Q

what chemical differences can the “R” groups have?

A

polar/nonpolar

acid/base

others

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6
Q

what determines the proteins function?

A

structure of the protein

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7
Q

what is the key to life as we know it?

A

protein structure

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8
Q

define polypeptide

A

a string of amino acids linked together in a chain by peptide bonds

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9
Q

where do peptide bonds join the amino groups?

A

at the amino group of one end to the carboxyl group of another amino acid

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10
Q

what type of bond is a peptide bond?

A

covalent

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11
Q

dehydration rxn

A

molecule of H2O is lost to form a peptide bond

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12
Q

hydrolysis rxn

A

H2O is added to break a peptide bond

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13
Q

what direction do the O and H point in a peptide bond

A

opposite directions

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14
Q

can the peptide bond rotate?

A

no, it’s planar b/c part of O’s double bond is delocalized onto the N

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15
Q

sequence of polypeptide backbone

A

NCCNCCNCCN

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16
Q

In polypeptide sequence what # covalent bond is a peptide bond?

A

Every 3rd

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17
Q

When can a polypeptide be called a protein?

A

If it has a biological function and is long

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18
Q

Small vs. large proteins

A

Small can be less than 100 amino acids

Large can be more than 30,000

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19
Q

What happens when proteins are digested?

A

Broken into small polypeptides then into amino acids

20
Q

Strand polarity (directionality)

A

Amino end and carboxyl end

Proteins are started at the amino end

New amino acids added to carboxyl end

21
Q

What determines the folding pattern of the protein?

A

Amino acid sequence

22
Q

Primary structure

A

Sequence of amino acids coded in the gene

23
Q

Secondary structure

A

Hydrogen bonds between parts of the backbone

Two types of structure

24
Q

Helixes

A

Alpha helixes are 2ndary

Coiled structure w/ side groups of amino acids sticking out from the sides

25
Q

Sheets

A

Beta pleated sheets are 2ndary

Straight regions held side by side

Parallel or antiparallel or both

Amino acid side groups stick out from both sides of the sheet

26
Q

Tertiary structure

A

Interactions between amino acid side groups

Affected by interaction of side groups w/ H2O

Involves covalent, ionic, hydrogen, and Van Der Waals bonds

27
Q

Water molecules pull polar groups to the ____ and push non polar groups to the ____

A

Outside, inside

28
Q

What environmental factors affect the folding of proteins?

A

pH, salt concentration, and heat

29
Q

Quaternary structure

A

A protein with several polypeptides

30
Q

What are the parts of a nucleotide?

A

Sugar, phosphate, and base

31
Q

What is another name for a nucleic acid?

A

Polynucleotide – a polymer (string) of nucleotides

32
Q

Two types of sugars in a nucleotide

A

DNA or RNA found on the 2’ carbon

Deoxyribose – DNA has two Hs

Ribose – RNA has an OH and an H

33
Q

Phosphate

A

Acidic

Forms connecting bridges between the sugars

Attach to the sugar at 3’ and 5’

34
Q

The backbone of RNA and DNA is alternating _____

A

Sugar and phosphate

35
Q

Bases in nucleic acids

A

Flat rings made of C & N attach to 1’

Adenine, Thymine

Guanine, Cytosine

Uracil (only in RNA)

36
Q

New units of nucleotide add to which end?

A

3’

37
Q

can RNA & DNA both form double helixes?

A

yes, but dsDNA is more common

38
Q

what holds the double helix together?

A

hydrogen bonding between base pairs

39
Q

A attaches to T with ___ bonds and G attaches to C with ___ bonds

A

2, 3

40
Q

when can two single strands of nucleic acids form a double helix?

A

if the strands are oriented in opposite directions

if the bases are complementary

41
Q

The sequence of bases in DNA is…

A

A genetic code that is read and used to make proteins

42
Q

How is DNA stored and utilized?

A

Stored in chromosomes and utilized in the form of short RNAs

43
Q

How does a cell use DNA?

A

Copies genes into short ssRNA

44
Q

What are ssRNA copies called?

A

mRNA

45
Q

Where are mRNA transported to?

A

Ribosomes in the cytoplasm

46
Q

The molecular secret of life is…?

A

Strings of DNA code for strings of amino acids