Chapter 3 - Biological Molecules Flashcards by darya .

what is a polymer

long chain molecules made up by the linking of multiple monomers in a repeating pattern

How well did you know this?

Not at all

Perfectly

what is a condensation reaction

a reaction which joins monomers by chemical bonds and it involves the elimination of a water molecule

How well did you know this?

Not at all

Perfectly

what is hydrolysis

when water is added to break a chemical bond between two molecules

How well did you know this?

Not at all

Perfectly

what chemical elements make up carbohydrates

carbon, hydrogen and oxygen
general formula: Cx(H2O)x

How well did you know this?

Not at all

Perfectly

what chemical elements make up lipids

carbon, hydrogen and oxygen

How well did you know this?

Not at all

Perfectly

what chemical elements make up proteins

carbon, hydrogen, oxygen, nitrogen and sulfur

How well did you know this?

Not at all

Perfectly

what chemical elements make up nucleic acids

carbon, hydrogen, oxygen, nitrogen and phosphorous

How well did you know this?

Not at all

Perfectly

structure of water (polar)

each hydrogen shares a pair of e- with oxygen
e- closer to oxygen as it has a greater affinity for them
oxygen δ- and hydrogen δ+
molecule is polar as it has two charged regions

How well did you know this?

Not at all

Perfectly

how do hydrogen bonds occur between water molecules

the δ- charge on the oxygen attracts the δ+ hydrogen on another water molecule

How well did you know this?

Not at all

Perfectly

high boiling point of water

has a high specific heat capacity due to many stable hydrogen bonds between molecules
large amount of energy required to break the bonds

How well did you know this?

Not at all

Perfectly

why is ice less dense than water

below 4oC hydrogen bonds fix the positions of H2O molecules further apart than in liquid state

How well did you know this?

Not at all

Perfectly

cohesion of water molecules
give eg

water molecules attract each other and move as one mass
eg. plants draw water up from roots/ surface tension

How well did you know this?

Not at all

Perfectly

adhesion of water

water molecules are attracted to other surfaces

How well did you know this?

Not at all

Perfectly

water as a coolant

high specific heat capacity buffers temperature changes on chemical reactions eg. for enzymes that may denature

How well did you know this?

Not at all

Perfectly

other uses of water

habitat

How well did you know this?

Not at all

Perfectly

what is a hexose monosaccharide,

has 6 carbons

How well did you know this?

Not at all

Perfectly

types of glucose

alpha and beta

How well did you know this?

Not at all

Perfectly

alpha glucose

OH on carbons 1 and 4 on same plane
down on carbon1

How well did you know this?

Not at all

Perfectly

beta glucose

OH on carbons 1 and 4 on opposite planes
up on carbon1

How well did you know this?

Not at all

Perfectly

solubility of glucose

polar due to OH groups so hydrogen bonds can form with water
dissolved in cytosol of cell

How well did you know this?

Not at all

Perfectly

type of bond between monosaccharides

glycosidic

How well did you know this?

Not at all

Perfectly

general condensation reaction of sugars

monosaccharides —> disaccharide + h2o

How well did you know this?

Not at all

Perfectly

which carbons does a glycosidic bond form between usually

1 and 4

How well did you know this?

Not at all

Perfectly

glucose + glucose

maltose

How well did you know this?

Not at all

Perfectly

glucose + fructose

sucrose

glucose + galactose

lactose

examples of hexose monosaccharides

glucose, fructose and galactose

what is a pentose monosaccharide

sugars that contain 5 carbons

examples of pentose sugar + explain

ribose: sugar present in RNA nucleotides deoxyribose: sugar present in DNA nucleotides

how do polysaccharides break down into simpler sugars

hydrolysis reactions

what 2 polysaccharides make up starch

amylose and amylopectin

what is starch

chemical energy store of glucose made in photosynthesis for plants

structure of amylose

alpha glucose joined by 1,4-glycosidic bonds coiled chain in helix stabilised by hydrogen bonding helix shape = compact and less soluble than glucose

structure of amylopectin

alpha glucose joined by 1,4-glycosidic bonds and some 1,6-glycosidic bonds branched structure due to 1,6 bonds

structure of glycogen

alpha glucose 1,4 and 1,6-glycosidic bonds more branching so more compact as animals have higher metabolism

what is the benefit of branched polysaccharide chains

free ends for glucose to break off quicker

structure of cellulose

beta glucose molecules 1,4-glycosideic bonds, alternate molecules rotate 180 degrees due to position of OH groups straight chain

how do cellulose chains join together

form hydrogen bonds with eachother forming microfibrils that join to make macrofibrils that join to form insoluble fibres in plant cell walls

What are triglycerides made up of

1 glycerol 3 fatty acids

What is the synthesis of triglycerides called, what type of reaction is it

Esterification, condensation

‘Equation’ for esterification

Glycerol + 3fatty acids -—-> triglyceride + 3H2O

Name of bond between fatty acids and glycerol

Ester bond

How much water does the hydrolysis of a triglyceride require

3 molecules

Saturated fat (triglyceride)

No C=C bonds in fatty acids

Saturated fat (triglyceride)

No C=C bonds in fatty acids

Monounsaturated fatty acid

1 C=C bond in fatty acid

Polyunsaturated fat

More than one C=C bond in fatty acid

Structure of phospholipid

- hydrophilic polar phosphate head - 2 hydrophobic non polar fatty acid tails

Cholesterol function

Stabilise cell membranes and regulate membrane fluidity

Primary structure of protein

The sequence of amino acids in the polypeptide chain

Secondary structure of a protein

The folding of a polypeptide chain into an alpha helix or beta pleated sheet by hydrogen bonding

Tertiary structure of a protein

The 3D folding of a polypeptide chain by interactions between R-groups

Interactions between side groups of tertiary protein structure

Hydrogen bonds Ionic bonds Discúlpate bridges Hydrophobic interactions Hydrophilic interactions

Quaternary protein structure

2 or more polypeptide chains joined together

Globular protein structure

Globe shaped Hydrophilic side groups Water soluble

Types of globular protein

Insulin Protease Haemoglobin

Properties of insulin and protease as globular proteins

Can diffuse through cells to bind to specific receptors

What is a conjugated protein

Containing a non-amino acid part in its structure (prosthetic group)

Haemoglobin

Globular, conjugated 4 haem groups (prosthetic) that contain iron

Structure of fibrous proteins

Proteins made up of strands and fibres Hydrophobic side groups Insoluble in water

Types of fibrous proteins and their functions

- collagen: strengthens tendon, bones and blood vessel walls - elastin: increase flexibility in cartilage eg. Alveoli and artery walls - keratin: strengthens hair, skin and nails

Biuret test

- Biuret (NaOH and CuSO4) added to sample, mixed and left - if protein present, colour change from blue to purple

Iodine test

- iodine dissolved in potassium iodide - added and mixed into sample - if starch present colour change from yellow/ brown to purple/ black

Emulsion test

- mix sample with ethanol then water and shake - if lipid present a white emulsion will form

Benedict’s test for reducing sugars

- sample in boiling tube -add equal volume Benedicta solution - heat gently in water bath - reducing sugar present colour change ( red precipitate)

Example of reducing sugar

Maltose and lactose

What to do if testing a solid sample

Grind up with water

Test for non-reducing sugars

- Benedicts test (negative) - hydrolyse by boiling with dilute hydrochloride acid - Benedicta test positive

Example of non reducing sugar

Sucrose