Low effort easy marks

5 chemicals required for life

1. Water

2. Carbon (food)

3. Nitrogen (DNA, RNA, amino acids/proteins)

4. Phosphorous (ATP)

5. Sulphur

Which nitrogenous bases are purines/pyrimidines and how many hydrogen bonds between them all?

Purines (double ring structure): Adenine and Guanine

Pyrimidines (single ring structure): Cytosine and Thymine/Uracil

3 hydrogen bonds: Guanine and Cytosine 

2 hydrogen bonds: Adenine and Thymine/Uracil

What direction is DNA replicated/RNA synthesised?

5’ to 3’ with new nucleotides being added at the 3’ end

Examples of monosaccharides, disaccharides and polysaccharides

Monosaccharides

• glucose

• fructose

• galactose

• ribose

Disaccharides

• maltose

• sucrose

• lactose

Polysaccharides

• starch

• cellulose

• glycogen

Name the bonds between monomers of macromolecules 

Nucleotides: Phosphodiester bond 

Polysaccharides: Glycosidic bond 

Triglyceride (3 fatty acid chains bound to glycerol): Ester bond 

Polypeptides: Peptide bond

Compare and contrast the isomers of glucose

1. Alpha glucose: hydroxyl group below

• Makes up glycogen, starch

1. Beta glucose: hydroxyl group above 

• Makes up cellulose

Compare and contrast the different types of starch

Describe cellulose

Compare different types of fatty acids

• Saturated fatty acids (no double bonds)

• Unsaturated fatty acids (double bonds in hydrocarbon chains)

  • Mono (one double bond) vs poly (multiple double bonds)

  • Cis (hydrogen on the same side) vs trans (hydrogens have opposing orientation)

Draw and label a diagram of a peptide bond between two amino acids 

List the bonds in each structure of proteins

1. Primary: peptide bonds (polypeptides)

2. Secondary: hydrogen bonds (alpha helix vs beta pleated sheet)

3. Tertiary: disulfide bridges (covalent), hydrogen bonds, ionic bonds, and hydrophobic interactions (between R groups to achieve 3D structure)

4. Quaternary: Bonds between multiple polypetide chains

   1. Conjugated: combine with non amino acid material

   2. Non conjugated: only made up of amino acids

What happens to proteins in different pH and temperatures?

Low pH: Denaturation 

High pH: Denaturation 

Low temp: Inactive 

High temp: Denaturation

Identify organelles found in prokaryotes vs eukaryotes

All living things have:

• Plasma membrane

• Cytoplasm

  • Cytosol

• DNA

• Ribosomes

List different types of membrane proteins

Integral proteins: Embedded in lipid bilayer, ampiphatic, mostly transmembrane but some are only on one side

• Channel proteins: Form channels/pores for membranes to pass through

• Carrier proteins: Undergo conformational change to transport molecules 

• Aquaporins: hydrophilic inside channel to allow for transport of water molecules without need for osmosis 

Peripheral proteins: Hydrophilic, membrane surface

• Receptors: receive chemical signals and act as binding sites (for hormones or neurotransmitters)

Define ventilation terms

• Total lung capacity: Total volume of air in the lungs after taking the biggest breath

• Forced vital capacity: After taking the biggest inhale, how much of that air you can exhale

• Residual volume: The amount of air your lungs must have in them to avoid collapse

• Tidal volume: Volume of air that moves in and out of lungs in a normal breath

• Inspiratory reserve: Difference between tidal volume and total lung capacity

• Expiratory reserve: Difference between tidal volume and residual volume

Compare arteries, veins and capillaries

Describe the two different types of speciation

1. Allopatric: speciation in different environments (geographical isolation)

2. Sympatric: speciation within the same environment (temporal isolation or behavioural isolation)

Describe adaptive radiation

Adaptive radiation: Common ancestor splitting into multiple species due to different variations exploiting different ecological niches.

• Minimises competition

• ex: Darwin’s finches developing different shaped beaks in line with the food source on their island

Describe polyploidy 

Polyploidy: When homologous chromosome sets contain more than two (are not diploid)

Define anthropogenic

Anthropogenic: Caused by humans

Describe formula for Simpson’s Diversity Index

High index when there is a high

• Richness (lots of different species)

• Evenness (not dominated by one species)

Direction of DNA processes

• DNA sense/coding strand 5’ to 3’

• DNA antisense/template strand 3’ to 5’

  • DNA read in 3’ to 5’ direction for transcription (antiparallel to the mRNA being synthesised in a 5’ to 3’ direction)

Lytic vs lysogenic cycle of the bacteriophage lambda

Neonicotinoid effect on neural signalling

Sister chromatids vs homologous chromosomes

Sister chromatid: identical copies of a single chromosome

• created during DNA replication, and are joined at the centromere

Homologous chromosomes: pair of chromosomes

• one inherited from each parent

• same size, shape, and genes

• but may carry different versions (alleles) of those genes

Describe mature mRNA

Mature mRNA is a product of post transcription modification in the nucleus

• 5’ cap and poly A tail added

• exons spliced together

The poly A tail slows the rate of degradation

Describe epigenetic tags

Epigenetic tags: Chemical modifications that cause some genes to be activated and others to be silenced.

• Doesn’t affect the gene itself, just the pattern of gene expression

• Facilitates differentiation as all cells have the same genome but their function is dependent on their expression

• Can be passed to offspring

Describe methylation 

Methylation: A type of epigenetic tag that involves the addition of a methyl group

• Methylation of the promoter region of a gene inhibits transcription 

• Methylation of histone proteins can change how available DNA is to transcription factors 

Xylem and phloem in plant root vs plant stem

Describe disruptive, stabilising and directional selection

Disruptive: Both extreme phenotypes are favored over the intermediate one

Stabilising: The intermediate phenotype is favored, and extreme variations are selected against.

Directional: One extreme phenotype is favored, causing the population's average trait value to shift over time.