Biology paper 1

• mRNA binds to ribosome

• Idea of two codons/binding sites

• Allows tRNA with anticodon to bind

• Catalyses formation of peptide bond between amino acids (held by tRNA)

• moves along mRNA to the next codon

• introns in pre-mRNA

• Removal of introns/ splicing to produce mRNA

• Polysaccharide of alpha glucose

• Joined by glycosidic bonds

• Branched structure

• Membrane folded so increased/large surface area

• Large number of protein channels for facilitated diffusion

• Large number of protein carriers for active transport

• Large number of protein channels/carriers for co-transport

• higher assault results in lower water potential of tissue fluid

• So less water returns to capillary by osmosis

• Binary fission

• Replication of circular DNA

• Division of cytoplasm to produce two daughter cells

• Each single copy of circular DNA

• both the denatured by high-temperature

• Nature faster at 60°C due to more kinetic energy

• Breaks hydrogen/ionic bonds between amino acids

• Change in shape of the Active site ( no longer complimentary) so fewer enzyme-substrate complexes formed

• hydrolyse peptide bonds to release amino acids

• Amino acids can cross cell membrane

• Phagosome/vesicle fuses with lysosome

• Virus destroyed by lysozymes

• Peptides/antigen are displayed on the cell membrane

1. Helper T cell/TH cell binds to the antigen (on the antigen-presenting cell/phagocyte);

2. This helper T/TH cell stimulates a specific B cell;

3. B cell clones

Or

B cell divides by mitosis;

4. (Forms) plasma cells that release antibodies;

• The antibody against virus antigen will bind to collagen

• This result in the destruction of the human collagen/cells

• tracheoles Half thin wall so short diffusing distance to cells

• Highly branched so short diffusion distance to cells

• Highly branched so large surface area for gas exchange

• Tracheae provide Chiefs full of air so fast diffusion into insects tissues

• Fluid in the end of tracheoles that moves out into tissues during exercise so faster diffusion through the air to the gas exchange surface

• Body can be moved by muscles to move air so maintains diffusion gradient for oxygen/carbon dioxide

Two chromosomes that carry the same gene

Prokaryotic DNA is

• circular

• Not associated with histones

• Only one molecule of DNA

A measure of the number of different species in a community

• reduces activation energy

• Due to bending bonds

More than one codon codes for a single amino acid

• trachea, bronchi, bronchioles, alveoli

• ^ ( in order)

Breathing in

• Diaphragm contracts and external intercostal muscles contract

• Volume increase and pressure decrease in thoracic cavity

Breathing out

• diaphragm relaxes and internal intercostal muscles contract

• Volume decrease and pressure increase in thoracic cavity

• both contain ester bonds

• Both contain glycerol

• Fatty acids on both may be saturated or unsaturated

• Both are insoluble in water

• Both contain carbon, hydrogen and oxygen but phospholipids also contain Phosphorus

• Triglycerides have 3 fatty acids and phospholipids have 2 fatty acids plus phosphate group

• Triglycerides are hydrophobic and phospholipids have hydrophilic and hydrophobic region

• Phospholipids form micelle/bilayer in water but triglycerides don’t

• plasma protein remain

• Created water potential gradient

• water moves to blood by osmosis

• Returns to blood by lymphatic system

Muscle contracts

Constricts/narrows lumen

• Index of diversity also measures abundance of each species

• So useful because maybe many of some species

• Attachment proteins attached to receptors on helper T cell

• RNA enters cell

• Reverse transcriptase converts RNA to DNA

• Viral proteins produced

• Virus assembled and released from cell

• RNA converted into DNA using reverse transcriptase

• DNA inserted into cell’s DNA/ nucleus

• DNA transcribed into mRNA

• HIV mRNA Translated into new HIV proteins for assembly into viral particles

• engulfs

• Forming vesicle/phagosome and fuses with lysosome

• Enzymes/ lysozymes digest pathogen

• B cell binds to specific/ complementary antigen

• B cell divides by mitosis

• Plasma cells produce antibodies against the virus

• B cells produce memory cells

Antibodies with the same tertiary structure

• first antibody (complementary in shape) binds to antigen

• Second antibody with enzyme attached is added

• Second antibody attaches to antigen

• Substrate/solution added and colour changes

• Bind to antigen

• Cause agglutination

Or

• attract phagocytes

1. Micelles include bile salts and fatty acids;

2. Make the fatty acids (more) soluble in water;

3. Bring/release/carry fatty acids to cell/lining (of the ileum);

4. Maintain higher) concentration of fatty acids to cell/lining (of the ileum);

5. Fatty acids (absorbed) by diffusion;

• elastic recoil of the aorta wall/tissue

• Smooths the blood flow

Or

• maintains the rate of blood flow

Or

• maintains blood pressure

• DNA that does not code for polypeptides

• Positioned between genes

1. (mRNA attaches) to ribosomes

OR

(mRNA attaches) to rough endoplasmic reticulum;

2. (tRNA) anticodons (bind to) complementary (mRNA) codons;

3. tRNA brings a specific amino acid;

4. Amino acids join by peptide bonds;

5. (Amino acids join together) with the use of ATP;

6. tRNA released (after amino acid joined to polypeptide);

7. The ribosome moves along the mRNA to form the polypeptide;

1. Hydrogen bonds (between DNA bases) break;

2. (Only) one DNA strand acts as a template;

3. (Free) RNA nucleotides align by complementary base pairing;

4. (In RNA) Uracil base pairs with adenine (on

DNA)

OR

(In RNA) Uracil is used in place of thymine;

5. RNA polymerase joins (adjacent RNA)

nucleotides;

6. (By) phosphodiester bonds (between adjacent nucleotides);

7. Pre-mRNA is spliced (to form mRNA)

OR

Introns are removed (to form mRNA);

• Change in the base/ nucleotide sequence of chromosomes/DNA

• Results in the formation of new allele

• Smaller groups within larger groups

• With no overlaps

• same genus

• Same evolutionary origin/ common ancestor

A form of immunity provided by the immune response of the body upon detection of a pathogen.

A form of immunity provide by the introduction of antibodies to a disease into the body

The ability to distinguish two different points in a specimen

A feature of an organism that increases its chance of survival in its environment.

a version of a gene

It is a type of classification that divides organisms into groups based on their analogous characteristics (leaf shape, number of legs)

The variety of genes, species and habitats within a particular area

A type of selection that favours individuals that differ in one direction from the population mean

The number of different alleles in a population

The entire set of genes in a cell

The position of a gene on a chromosome

An agent that increases the rate of gene mutations above normal levels.

A type of classification that divides organisms into groups based on evolutionary relationships and homologous characteristics.

Each group within a phylogenetic classification system

• joining two molecules

• Creating a chemical bond

• Removing water

• breaks a chemical bond

• Between two molecules

• Use of water

• Amylopectin - unbranched, increases surface area for rapid hydrolysis

• Amylose - unbranched helix, compact

• Insoluble so doesn’t effect water potential

• Large so cannot leave cell

• long straight chains, hydrogen bonds in between

• Many hydrogen bonds, microfibrils to fibrils result in collective strength

• Against hydrostatic pressure

• Insoluble - doesn’t effect water potential of cell

• highly branched so large surface area for hydrolysis into glucose

• Very important as animals have a high metabolic rate

• Insoluble so doesn’t affect water potential of cell

• energy store (large ratio of energy storing C-H bonds)

• Metabolic water source (large ratio of C-H bonds which can release water when oxidised)

• Insoluble as hydrophobic (doesn’t effect water potential)

• Relatively low mass

• Sequence of amino acids in the polypeptide chain

• Sequence of amino acids causes parts of a protein molecule to bend

• Alpha helix or beta pleated sheet

• hydrogen bonds

• further folding of the secondary structure

• Unique 3D structure

• Hydrogen bonds , ionic bonds and disulphide bridges

More than one polypeptide chain

• tertiary structure protein

• Lowers activation energy

• of reactions it catalyses

• active site changed shape slightly to fit substrate

• Puts strain on the bonds

• Lowers activation energy

Too low

• not enough kinetic energy for successful collisions

Too high

• enzymes denature

• Active site changes

• Enzyme substrate complexes cannot form

• interfere with charges on amino acids/ ionic bonds in the active site

• Bonds break holding tertiary structure in place

• Active site changes

• Enzyme denatured

• Fewer enzyme substrate complexes form

• same shape of substrate

• Binds to active site

• Prevents enzyme substrate complexes forming

if you add more substrate it will flood/out-compete the inhibitor, knocking them out of the active site.

• binds to allosteric site (another site other than active site)

• Causes active site to change shape

• No enzyme substrate complexes

The substrate can no longer bind, regardless of how much substrate is added.