Biological molecules

Name the 9 properties of water

-High latent heat of vapourisation

-High specific heat capacity

-surface tension

-ice is less dense than water

-metabolic

-solvent

-cohesion

-liquid at room temperature

Is amylopectin a

Polymer

Monomer

EQ

Polymer

Is glucose a

Monomer

Polymer

EQ

Monomer

Is sucrose a

Polymer

Monomer

EQ

Neither it is a polysaccharide

Describe the bond between 2 glucose monomers in maltose

EQ

Alpha 1-4 glycosidic bond

What is the molecule formula of lactose

EQ

C 12 H22 O11

Right one

Outline how the properties of glucose relate to its function

EQ

Soluble

Source of energy

Outline how the properties of starch and glycogen relate to their functions

EQ

Energy storage

Insoluble

compact

Explain how the structure of glucose allows it to move from the plant to the bacterium

EQ

Small so can cross membranes

OH groups allow bonding with water molecules.

A common symptom of lactose intolerance is the creation of extra fluids in the large intestine

Suggest why this occurs

EQ

Undigested lactose lowers H2O potential

Water enters by osmosis

True or false:

Lipids that contain fatty acids with carbon carbon double bonds are liquid at room temperature

EQ

True

Name 2 groups involved in an amino acid

EQ

Carboxyl

Amino

What bonds are present in the tertiary structure

EQ

Disulfide Bonds

Name the enzyme in an erythrocyte that allows haemoglobinic acid to be formed

EQ

Carbonic hydrase

Name and describe the reaction that produces amino acids from polypeptides

EQ

Hydrolysis

Peptide bonds broken

State 2 properties of collagen

EQ

Fibrous

Insoluble

Are disulfide bonds involved in the secondary structure

EQ

No

True or false

Each single polypeptide chain in secondary structure is either alpha helix or beta pleated sheet

EQ

False

can be alpha helix and beta pleated in the same chain

Name the bond present in the primary structure of a protein

EQ

Peptide bond

Name the structure labelled x

Haem

Effect of cohesion on water molecules

EQ

Holds water molecules together

Which bond is not formed when a conjugated protein folds into its quaternary structure

Disulfide

Hydrogen

Ionic

Peptide

EQ

Peptide

What does starch hydrolyse to?

EQ

Glucose

Explain what is meant by a conjugated protein

EQ

Prosthetic group

Attached by covalent bonds

Contains non protein groups

Describe how the structure of llama haemoglobin is likely to be different from that of a camel haemoglobin

EQ

Different primary structure

Different base sequence

No change to quaternary structure

Different secondary structure

State 3 properties of fibrous protein that are different from those of a globular protein

EQ

Insoluble

Strong

Unreactive

Properties and functions of fibrous proteins

EQ

Insoluble strong flexible

Collagen in bones

Keratin in hair -protection

Elastin-elasticity in artery walls

functions of fibrous proteins

EQ

Enzymes -catalyse reactions

Hormones-cell signalling

Transport -haemoglobin to carry oxygen

Describe and explain why collagen is a fibrous protein

EQ

Long chain

No tertiary structure

Insoluble

Suggest why collagen is such a strong molecule

EQ

Many hydrogen bonds

Explain how hydrophilic and hydrophobic interactions contribute to the spherical shape of ferritin

EQ

Hydrophobic inside molecule

Hydrophilic outside molecule

Name the covalent bonds Contains non that links 2 cysteine amino acids

EQ

Disulfide links

Name the type of monomer from which collagen is made and explain how two such monomers are joined together

EQ

Amino acid

Peptide bonds

In a condensation reaction

Order these from most soluble to least soluble

Ribose

Amylose

Glucose

Amylopectin

EQ

Glucose

Ribose

Amylose

Amylopectin

What type of glucose molecules is amylopectin made of?

EQ

Alpha glucose

What is amylose made of?

EQ

Alpha glucose molecules

Describe the formation of chitin molecule from its monomers

EQ

Bonds formed by condensation reactions

Water released

Alternate monomers flipped by 180 (because made of N-acetylgluocsamine made fo beta glucose molecules)

Because of the OH groups

Describe and explain the structure and properties of lipids

EQ

Energy rich

More carbon carbon bonds

Insoluble compact

Long chains can be broken down to release 2 carbons

Describe and explain the structures and properties of different carbohydrates

EQ

Polymers of glucose

-glucose used in respiration

Large molecules

Insoluble-doesn’t affect water potential

State 2 ways in which the molecular structure of cholesterol is similar to the molecular structure of glucose

EQ

Contains carbon and hydrogen

Contains oxygen

State the physical property of glucose that allows it to be easily transported into the bloodstream

EQ

Glucose is soluble

Is glucose compact?

EQ

No

State 2 structural similarities between lactose and maltose

EQ

Two hexoses

1-4 glycosidic bond in both

Identify the differences between the structures of lactose and maltose

EQ

Lactose:

Beta glucose

Beta glycosidic bonds

Sugars in opposite direction

Maltose:

Alpha glucose

Alpha glycosidic bonds

Same direction monomers

Suggest why lactose is unable to cross membranes

EQ

Unable to pass between phospholipids

As too large

Give 3 properties of cellulose that make it suitable as the basis of plant cell walls

EQ

High tensile strength

Insoluble

Flexible

2 Similarities between chitin and glycogen.

EQ

Polymers

1-4 glycosidic bonds

2 differences between the structures of chitin and glycogen

EQ

Chitin has nitrogen

No 1-6 glycosidic bonds in chitin

How does branching affect the process of respiration

EQ

Speeds up hydrolysis

As more free ends

Is amylose soluble

EQ

No

Which phase of interphase has the least DNA?

EQ

G1

Which phase of interphase has the highest number of cells

EQ

G1

Why would one cell spend more time in the S phase?

EQ

It has more DNA than the other cell

State one observation of a white blood cell that has stopped dividing in at the G2

EQ

Large number of organelles

During which stage of the cell cycle does semi-conservative DNA replication take place?

EQ

Synthesis phase

State 2 roles of mitosis in multicellular organisms

EQ

Production of new stem cells

Asexual reproduction

Why do plant reproduce asexually when conditions are favourable

EQ

Genetically identical offspring produced rapidly

Describe the spindle fibres

EQ

Spindle fibres attach to chromosome

Explain why type of nuclear division in a zygote is mitosis and not meiosis

EQ

Genetically identical clones To grow into an embryo

Prophase

Explain how the organisation of homologous chromosomes during metaphase1 Increases genetic variation

EQ

Each chromosome of homologous chromosomes pair is genetically different

Chromosomes line up across center of cell

Other than having specific receptors describe one way in which the structure of the neutrophil is specialised

EQ

Well developed cytoskeleton

Describe the changes that must occur inside these stem cells as they differentiate to form erythrocytes

EQ

Digest organelles associated with protein synthesis

Suggest 3 ways in which the use of embryonic stem cells in reasearch has practical benefits to biological knowledge

EQ

Test effectiveness of new medical drugs

Test side effects of new drugs

Studied to se how develop into different cell types

Explain the difference between a muscle tissue and a muscle

EQ

Muscle tissue is a collection of dif cells that contract together

Muscle is an organ and a collection of tissues

Explain the benefits to plants on internal transport systems

EQ

High metabolic rate

Ensures nutrients reach all tissues

Where are companion cells located

EQ

Phloem

Example of substance transported by a companion cell

EQ

Sucrose

Example of substance transported by a root hair cell

EQ

Nitrate ions

Does a guard cell have chloroplasts

EQ

Yes

Explain why a leaf is described as an organ

EQ

Leaves have phloem and xylem to carry out photosynthesis

And organ definition

Explain why podocytes are unable to undergo mitosis

EQ

• Have already differentiated

• In G0 phase

• Shape too irregular

What features of adult stem cells make them suitable for regeneration of tissues in the kidney

EQ

Adult stem cells are multipotent and can differentiate into any cell type

Identify the structures

U

W

Z

U-matrix

W-cristae

Z-inter membrane space

Explain the role of embryonic stem cells in the development of the embryo

EQ

Renewing source of cells

Can differentiate into any cell type

Totipotent

EQ

Can form whole organisms

Can’t give rise to extra embryonic tissues

Do mature sieve tube elements contain nuclei

EQ

Yes

Do xylem vessels have non lignified pits to allow movement in and out

EQ

Yes

Are companion cells linked to xylem vessels by plasmodesmata

EQ

No

Is the cell wall thicker or thinner on the side furthest away from the stoma

EQ

Thinner

Squamous epithelial

EQ

Flattened shape

Pack close together

Short diffusion distance

Describe an ethical issue associated with the use of embryonic stem cells

EQ

Embryo destroyed

used in IVF

What type of cell is present in meristematic tissue

EQ

Stem cells

How are xylem vessels formed from stem cells

EQ

Differentiation

Lignification

Cell elongation

How does the iodine test work

Iodine forms triiodide ion that enters the middle of the amylose helix causing the colour change

Colour change in iodine test

Brown to blue black

Method for testing for lipids

Take sample and mix with ethanol

Lipid dissolves in ethanol

Filter

Pour solution into water

Cloudy white precipitate forms if positive result

Why do you filter the ethanol test

To remove the undissolved ethanol

How does the burnet test work

Colour formed by complex between nitrogen atoms in peptide chain and cu2+ ions

Method for testing for proteins

Add 5ml of biuret solution to sample

If protein is present colour changes from blue to lilac

Colour change in biuret test

Blue to purple

Colour change in reducing sugar

Blue-no colour change

Green-little glucose

Amber-some glucose

Red-lots of glucose

Iodine dissolved in potassium iodide solution when heated disappears but when cooled returns why

Bonds break when heated

Biosensors

Machines that tell you if a biological molecule is present

How do you estimate the amount of a sample without using a biosensor

Compare with standard solution

Two functional groups in an amino acid molecule

Amine

Carboxyl

R group

True or false

Sucrose is a polymer

FALSE SUCROSE IS NOT A POLYMER

Quaternary structure in insulin

Polypeptide chains that are linked by disulfide bonds

Quaternary structure in haemaglobin

Two alpha globin chains and two beta globin chains

1 only