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Flashcards in Protein & DNA Deck (46)
1

what provides most of the molecular functions of life?

proteins

2

what is a protein / another name for a protein?

a string (polymer) of amino acids / polypeptide

3

amino acid structure

central alpha carbon

amino group NH2

carboxyl group CO2H

hydrogen atom

side chain "R" group

4

how many "R" groups are there?

20 -- different amino acids

5

what chemical differences can the "R" groups have?

polar/nonpolar

acid/base

others

6

what determines the proteins function?

structure of the protein

7

what is the key to life as we know it?

protein structure

8

define polypeptide

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

9

where do peptide bonds join the amino groups?

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

10

what type of bond is a peptide bond?

covalent

11

dehydration rxn

molecule of H2O is lost to form a peptide bond

12

hydrolysis rxn

H2O is added to break a peptide bond

13

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

opposite directions

14

can the peptide bond rotate?

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

15

sequence of polypeptide backbone

NCCNCCNCCN

16

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

Every 3rd

17

When can a polypeptide be called a protein?

If it has a biological function and is long

18

Small vs. large proteins

Small can be less than 100 amino acids

Large can be more than 30,000

19

What happens when proteins are digested?

Broken into small polypeptides then into amino acids

20

Strand polarity (directionality)

Amino end and carboxyl end

Proteins are started at the amino end

New amino acids added to carboxyl end

21

What determines the folding pattern of the protein?

Amino acid sequence

22

Primary structure

Sequence of amino acids coded in the gene

23

Secondary structure

Hydrogen bonds between parts of the backbone

Two types of structure

24

Helixes

Alpha helixes are 2ndary

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

25

Sheets

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

Tertiary structure

Interactions between amino acid side groups

Affected by interaction of side groups w/ H2O

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

27

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

Outside, inside

28

What environmental factors affect the folding of proteins?

pH, salt concentration, and heat

29

Quaternary structure

A protein with several polypeptides

30

What are the parts of a nucleotide?

Sugar, phosphate, and base

31

What is another name for a nucleic acid?

Polynucleotide -- a polymer (string) of nucleotides

32

Two types of sugars in a nucleotide

DNA or RNA found on the 2' carbon

Deoxyribose -- DNA has two Hs

Ribose -- RNA has an OH and an H

33

Phosphate

Acidic

Forms connecting bridges between the sugars

Attach to the sugar at 3' and 5'

34

The backbone of RNA and DNA is alternating _____

Sugar and phosphate

35

Bases in nucleic acids

Flat rings made of C & N attach to 1'

Adenine, Thymine

Guanine, Cytosine

Uracil (only in RNA)

36

New units of nucleotide add to which end?

3'

37

can RNA & DNA both form double helixes?

yes, but dsDNA is more common

38

what holds the double helix together?

hydrogen bonding between base pairs

39

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

2, 3

40

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

if the strands are oriented in opposite directions

if the bases are complementary

41

The sequence of bases in DNA is...

A genetic code that is read and used to make proteins

42

How is DNA stored and utilized?

Stored in chromosomes and utilized in the form of short RNAs

43

How does a cell use DNA?

Copies genes into short ssRNA

44

What are ssRNA copies called?

mRNA

45

Where are mRNA transported to?

Ribosomes in the cytoplasm

46

The molecular secret of life is...?

Strings of DNA code for strings of amino acids