biological molecules Flashcards Preview

A level Biology > biological molecules > Flashcards

Flashcards in biological molecules Deck (45):
1

what reaction binds monomers

condensation

2

what chemical is produced by a condensation reaction

water

3

what is the opposite of a condensation reaction

hydrolysis reaction

4

how are bonds broken in a hydrolysis reaction

water is added

5

what are carbohydrates

molecules that contain only carbon, hydrogen and oxygen.

6

what are the three types of saccharides

monosaccharides
disaccharides
polysaccharides

7

what bonds hold carbohydrate molecules together

glycosidic

8

what is an example of a monosaccharide

glucose

9

how is maltose formed

condensation of two glucose molecules

10

how is sucrose formed

condensation of glucose and fructose

11

how is glycogen and starch formed

the condensation of alpha glucose

12

how is cellulose formed

condensation of beta glucose

13

what glycosidic bonds does glycogen have

1-4 and 1-6 alpha

14

explain the structure of glycogen

large number of side branches
large but compact

15

what two polysaccharides is starch a mixture of

amylose
amylopectin

16

describe the structure of amylose

unbranched chain of glucose molecules joined by 1-4 glycosidic bonds
coiled
very compact so can store alot of energy

17

describe the structure of amylopectin

branched made up of glucose molecules joined by 1-4 and 1-6 glycosidic bonds
rapidly digested by enzymes
quick release of energy

18

what are the two types of lipids

saturated and unsaturated

19

which contain carbon -carbon double bonds; saturated or unsaturated lipids

unsaturated

20

what are triglycerides

lipids made of one glycerol and three fatty acids.

21

what bonds are involved with lipids

ester

22

what are triglycerides used as

energy reserves in plant and animal cells

23

what are phospholipids

lipids made of one glycerol, two fatty acids and one phosphate

24

explain the structure of phospholipids

hydrophilic head
hydrophobic tail

25

what monomers make proteins

amino acids

26

describe the structure of amino acids

amino group (NH2)
carboxylic group
and a variable R group

27

what bonds are amino acids joined by

peptide

28

what is the primary structure of a protein

the sequence of amino acids

29

what is the secondary structure of a protein

interaction between amino acids. the shape that the amino acids takes which is determined by hydrogen bonds

30

what two shapes can the secondary structure of a protein take

alpha helix
beta pleated sheet

31

what is the tertiary structure of a protein

the 3D shape of the protein. it can be globular or fibrous.

32

what interactions occur between R groups in the tertiary structure

hydrophobic and hydrophilic interactions
hydrogen bonds
ionic bonds
disulfide bonds

33

what are globular proteins

compact, water soluble and spherical in shape
formed when hydrophobic R groups are kept away from the aqueous environment and hydrophilic R groups are on the outside of the protein

34

what are conjugated proteins

globular proteins that contain a non protein component known as a prosthetic group

35

what are fibrous proteins

formed from long insoluble molecules.
due to high proportion of hydrophobic R groups in the primary structure.
amino acid sequence is usually quite repetitive.
not folded into 3D shapes

36

what are the components of a DNA nucleotide

deoxyribose
a phosphate group
one of the organic bases

37

what are the DNA organic bases

adenine
cytosine
guanine
thymine

38

what bases are pyrimadines

cytosine
thymine

39

what bases are purines

adenine
guanine

40

what are the components of an RNA nucleotide

ribose
a phosphate group
one of the organic bases

41

what are the RNA organic bases

adenine
cytosine
guanine
uracil

42

describe the structure of a DNA molecule

double helix
two polypeptides joined by hydrogen bonds between complementary bases
the two polypeptides lie antiparallel
phoshate sugar backbone

43

explain DNA replication

double helix unwinds and the hydrogen bonds between complementary bases break using DNA helicase.
both strands are used as templates and complementary base pairing occurs between the template strands and free nucleotides
adjacent nucleotides joined by phosphodiester bonds using DNA polymerase

44

explain transcription

in the nucleus
hydrogen bonds between complementary bases break and the DNA uncoils
one strand is used as a template by RNA polymerase to make a mRNA molecule. this strand is used as the anti sense strand
free nucleotides line up by complementary base pairing and adjacent nucleotides join by phosphodiester bonds by RNA polymrase.
mRNA then moves out of the nucleus and attaches to a ribosome

45

explain translation

mRNA attaches to a ribosome and tRNA collects amino acids from the cytoplasm and carries them to the ribosome.
tRNA attaches to mRNA by complementary base pairing
the amino acids joined to two tRNA molecules join by a peptide bond and the tRNA detach.
process repeated until a stop codon is reached