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Flashcards in biochemistry Deck (71):
1

describe the structure of a water molecule

one atom of oxygen joined to two atoms of hydrogen by shared electrons. Because the shared negative hydrogen electrons are pulled towards the oxygen atom the other side of the hydrogen atom is left with a slight positive charge. Unshared negative electrons on the oxygen atom give it a light negative charge. This makes water a polar molecule

2

state properties of water that make it useful for living organisms

waters polarity makes it useful as a solvent in living organisms e.g. important substances in biological reactions are ionic. Waters polarity makes it very cohesive, waters less dense when its solid, hydrogen bonds give water a high specific heat capacity and hydrogen bonds give water a high latent heat of evaporation

3

why when water freezes is it less dense?

water becomes denser with lowering temperature. When near freezing point presence of hydrogen bonds means the molecule form a structure that is of a lower density hence why it floats on water.

4

what is the difference between an alpha glucose molecule and a beta glucose molecule?

the H and Oh are flipped to be the opposite way- alpha OH is at the bottom and in beat OH is at the top.

5

what is the bond between monosaccharaides?

glycosidic

6

what are the reactions that join monosaccharides and split disaccharides and polysaccharides?

condensation joins and hydrolysis splits

7

what else is produced when monosaccharieds join?

water

8

what is required when disaccharides and polysaccharides split?

water

9

what are carbohydrates made up of?

carbon, hydrogen and oxygen

10

what are the roles of carbohydrates?

provide energy, provide support and energy storage

11

give 3 examples of hexose monosaccharides

glucose, fructose and galactose

12

what is the difference between ribose and deoxyribose?

ribose has an OH group but deoxyribose does not- deoxyribose does not contain oxygen

13

what monomers is maltose made of and where is it found?

2 alpha glucose molecules, it is found in brewing sugars and breakdown of starch

14

what monomers is sucrose made of and where is it found?

alpha glucose and fructose, found in table sugar and plants

15

what monomers is lactose made of and where is it found?

alpha glucose and galactose, found in milk

16

what property do storage carbohydrates need?

compact

17

what property do structural polysaccharides need?

straight chains

18

what is the repeating unit of storage polysachharides?

alpha glucose

19

what is the significance of an OH group on the storage polysaccharide?

it starts to make the polymer coil which gives the coiled compact shape

20

what is the storage carbohydrate for animals?

glycogen

21

what is the storage carbohydrate of plants and what is it made from?

starch, made from amylose and amylopectin

22

give the roles of proteins

cellular structure, movement, defense transport and communication

23

what is the role of enzymes?

regulate chemical reactions

24

what elements are proteins made of?

carbon, hydrogen, oxygen, nitrogen and sulfur

25

what is the monomer of proteins?

amino acids

26

how many types of amino acids are there?

20

27

what can am amino acid be described as and why?

amphoteric as it has both basic and acidic group atatched to it

28

what is it called when two amino acids join and what is the bond that is formed called?

dipeptide- peptide bond

29

what is the primary structure of a protein?

number, order and type of amino acid

30

what is the secondary structure of an protein?

alpha helix and beata pleated sheet produced by hydrogen bonding

31

describe a disulphide bond

where 2 cysteine AA are found together strong double (S=S) formed between the sulphur atoms within the cysteine monomers

32

describe an ionic bond

if 2 oppositley charged "R" groups are found close to each other ionic bonds form

33

describe hydrogen bonds

typical everyday hydrogen bonds not as strong as sulphide and ionic but lots of them

34

describe hydrophibic and hydrophilic bonds

in water based environment a globular protein will orientate itself such that its hydrophobic parts are towards its center and hydrophilic parts towards the otuside

35

what is the quaternary structure of a protein?

the relationship amongst many polypeptides of a protein

36

give the properties of long fibrous protiens

mostly consist of repeating squences of AA, insoluble in water due to high proportion of AA with hydrophobil "R" groups in the primary structure

37

what is the usual role of fibrous proteins?

structural roles

38

describe the structure of collagen

made of 3 polypeptides wound together in a long strong structure

39

give 4 uses of collagen

1- structure of bones , 2-cartilage & connective tissue, 3-prevents high pressure blood for bursting arteries 4- main component of tendons which connect bones to skeletal muscles

40

where is keratin found and what amino acid is in abundance?

outer layer of skin, hair and nails- large proportion of cysteine - lots of S=S bonds

41

what does the large proportion cysteine mean? what determines the flexibility

lots of strong sulphide bonds forming strong & insoluble materials. the amount of S=S bonds determines flexibility

42

where is elastin found?

in connective tissue, arteioles , arteies and alvioli of the lungs

43

what is the purpose of elastin?

allows tissue to return to shape after stretching and contracting also allows skin to retain shape after being stretched

44

properties of globular proteins & example

compact spherical shape and soluble, enzymes and antibodies

45

describe the folding of a globular protein

tertiary structure , folding ensures that the hydrophobic "R" groups are kept away from the aqueous environment , hydrophilic "R" groups are on the outside

46

describe the conjugated protein insulin

2- polypeptide chains - start alpha helix end beta pleated , both chains fold into a tertiary structure linked by dispulhide bonds, hydrophilic r groups on outside = soluble

47

what are conjugated proteins made of?

polypeptide, globular protein and prosthetic group

48

what are lipoprotein and glycoproteins ?

lipids or carbohydrates join with proteins to form lipoproteins or glycoproteins

49

describe the conjugated protein heamoglobin

2 aplha and beta polypeptide chains and inorgainic prosthetic haem group with each chain, the Fe2+ heam guop is where oxygen molecules bind

50

describe the conjugated enzyme catalase

has a quaternary structure made of 4 haem prosthetic groups. Fe2+ ion allows enzyme to interact with hydorgen peroxide- this is a common breakdown of metabolosim

51

what is the difference between an alkane and an alkene?

alkene has a double bond alkanes do not

52

what elements do lipids contain?

carbon, hydrogen & oxygen

53

why are lipids not polymers? what are they?

they have no repeating units they are called macromolecules

54

describe the behavior of lipids with water

they repel water and are relatively insoluble in water

55

where are lipids stored?

in adipose tissue in the skin

56

what are the roles of lipids?

structural components, insulation, hormone production, buoyancy in aquatic animals, respiration to release energy, produce more water than the respiration of water

57

why are lipids used as as an energy source?

1g of fat releases twice as much energy as 1g of glucose as they have a higher proportion of hydrogen atoms than carbohydrates and hardly any oxygen atoms

58

what is an essential fatty acid?

an acid that must be ingested

59

why is a fatty acid an acid?

hydrocarbon chain form 2 to 20 carbons long, carboxyl groups ionise into H+ and -COO- therefore an acid

60

what is the ratio of glycerol to fatty acids in a triglyceride?

one glycerol molecule linked to 3 fatty acids

61

whats the name of the bond formed , how many water molecules are produced in the formation of a triglyceride and what is the formation of the bond called?

ester, 3 and esterification

62

what is the difference between a saturated and unsaturated fatty acid?

saturated have no double bonds in the hydrocarbon chain, in an unsaturated fatty acid a kink is formed from the double bond making it more fluid

63

what is the result of the difference? Give and example of a saturated fatty acid and unsaturated fatty acid

unsaturated are liquid at room temperature e.g. plant oil and saturated are solid at room temperature e.g. lard

64

where are phospholipids found?

major component of cell membranes

65

how do phospholipids differ from triglycerides?

each have a hydrophilic head and 2 hydrophobic tails

66

what are is the hydrophilic head made of and what are the hydrophobic tails made of?

tail- 2 fatty acids, heads- glycerol and a phosphate group

67

what is another name for cholesterol?

strerol or steroid alcohol

68

describe the structure of cholestrol

4 carbon base rings -(isoprene)

69

where is it found and what does it do?

eukaryotic plasma membrane and regulates the fluidity of the membrane

70

where in the body is cholesterol made?

the liver

71

what can be made from cholesterol?

steroid hormones and vitamin D