- Created by: Marvo1245
- Created on: 15-03-20 05:01
4 main macromolecules of Life
Carbohydrates: Structure, fuel and stability.
- Monosaccharides, glucose
- Disaccharides, sucrose and fructose
- Polysaccharides, cellulose
- Fats (energy)
- DNA, RNA. and amino acids
- Store transmit and express genes
- Versatile building blocks and have many functions
Small inorganic molecules --> small organic molecules --> macromolecules --> Protocell
Life originated on another planet and was brought here by asteroid since Amino acids have been found on asteroids that do not originate on Earth.
multiple Hydroxyl groups attached.
When two sugars come together, the OH groups are hydrolysed to form a single Oxygen bond atom between the two
Have an amino group, H,N,H and a carboxyl group OH-C=O formed with an alpha carbon.
When nthe hydrogen molecule of the amino group and the hydroxyl group of the carboxyl side hydrolyse and form a straight chain
Read the amino acids left to right, single chain
Beta pleated sheets and Alpha helix interactions. Hydrogen bonds occur between the oxygen of the carboxyl group and the hydrogen atom of the amino group
- Hydrophobic interactions
- hydrogen bonding
- ionic bonding
- Disulphide bridges
- Van Der Waal forces
Creates overall shape of protein
More than two polypeptide chains interacting
In highly acidic, high concentrations of salt or environments that are too hot, the protein can become denatured which is why fevers are dangerous
DNA -> mRNA -> rRNA -> tRNA -> protein
DNA is transcripted into RNA, RNA is transcribed into a protein
Guanine, thymine, adenine, cytosine, uracil.
purines and pyramids
up to 3 phosphate groups
introns and exons
Introns do not code
exons do code
Having specialized organelles benefit larger cells since they can co-ordinate with each other and develop overtime
Basic needs of a cell
- carry genetic information
- maintain a different internal and external environment
- have metabolic activities
Nucleus + nucleolus (settings)
Control centre of the body, protects DNA
Rough Endoplasmic Reticulum (factory)
Makes proteins with ribosomes
Smooth endoplasmic reticulum
Makes hormones, lipids, detoxifies and stores calcium.
packages and matures proteins
digestive secretions for outside of the cell
integrates components into the cell
create lysosomes for digestion
catalase: makes bleach
oxidase: makes water
Stores water and food
Non-polar, uncharged and small lipids pass
polar, larger molecules with concentration gradient
primary active transport
Against concentration gradient, with ATP
Secondary active transport
against and with the concentration gradient. co-transport required
controlling solute concentration when living in an isotonic environment
Cells with a cell wall pushing back onto the ECF in hypotonic environments
Cells with cell wall pulling away from the cell wall in hypertonic environments
DNA is replicated at one point of origin, the DNA copies in both directions, the DNA supercoils with the assistance of a special protein, the cell size increases and then the cell divides.
Endothermic, Gibbs G and endergonic
Positive delta G value, anabolic reactions, non-spontaneous, requires energy
Exothermic, Giibs G, exergonic
negative Delta G, spontaneous, catabolic, releases energy
Inorganic molecules that assist in electron transfer.
Iron, magnesium and zinc.
organic molecules that assist in electron transfer
Behind the scenes of Evolution
- Mutations arise from genetic DNA errors.
- DNA polymerase: Makes an error in 1 in every 10,000,000
- Post-replication repair: Makes error in 1 in every 1,000,000,000
- Human genome: when a full human genome is replicated, there are usually 3 errors since they area 3,000,000,000
- Mutation: Bad
- Polymorphism: great or neutral
Insertion: a nucleotide is inserted into the amino acid sequence
Substitution: when a nucleotide is exchanged for another one in its place
Deletion: when a nucleotide is removed
Basis of evolution
Basis of evolution: In somatic cells --> mutations only affect individual, in gamete ---> mutations effect all offspring
A change in allele frequency in a population overtime
In diploid organisms, two alleles usually code for every genotype
Members of a population vary in their inherited trait. All species produce offspring that won’t be able to reproduce. Members with inherited traits which are beneficial are advantageous because it raises the probability of survival and offspring survival.
Descent with modification
Evolve overtime to better their environment
Evidences of Evolution
- Galapagos finches: Beak size and shape changed with food availability and rainfall
- Artificial selection: or selective breading. Domestication of animals for particular qualities. Different vegetables from common ancestors
- Antibiotic resistance: Initial antibiotic almost killed all bacteria but the few that survived passed on the resilience to their offspring
Morphological and genetic homology
Shared similarities between species to identify a common ancestor through anatomical homology
- Molecular Homology: DNA sequence that code for similar proteins across different species
- Amino Acid Sequence: Different species that have similar amino acid sequences that code for proteins
Physical record of intermediate life forms that support descent with modification
Mechanisms of Evolution
Natural selection: The most fit organisms reproduce more bcs they can compete better for resources. They have the most offspring who will also be well adapted thus the alleles that confer adaptive advantage increase in frequency in the population
o Direction selection: Favours variants at one end, black mice do better than white mice
o Disruptive selection: Favour variants at both extremes. White and black mice do well, intermediate coloured mix do not do well
o Stabilising selection: Favours variants from the intermediate population. Tan mice do better than black or white mice
o Maladaptation’s: Natural selection drives adaption and sometimes favours adaptions that aren’t all good. Peacock feather colouration gives its position away to predators
Fluctuations in allele frequency arising from chance events. Doesn’t always lead to adaptions since its random. Has a bigger impact with smaller populations?
- Founder effect: A small segment of the population goes someplace different and thus the alleles are way different
- Bottleneck effect: Occurs when population undergoes rapid decrease in size due to a natural disaster where only few live.
- Fixation: From genetic drift, some alleles can become fixed that are really bad
A result of population migration between two groups. this can diversify
Igneous rock: comes from cooling magma
Sedimentary rock: Formed by accumulation of sediment
Metamorphic: One of the above charged by the environment (pressure or heat)
Found in sedimentary rock.
- the carcass is buried in mud
- The soft tissue decomposes whilst the bone remains
- the sediment builds up top and hardens into rock
Fossil recorded by the layer of strata they're found in
- Radiometric decay/dating tells us absolute age. Based on predictable decay of radioactive isotopes (expressed as t.5) = 5730 years. When an animal dies, it stops accumulating elements. Ratio of radioactive isotopes to stable isotopes is directly related to how long ago it died.
- Fossil record bias: Subjected to bias to species that existed for a long time, were abundant and widespread and had hard-shells or skeletons
Homology vs Analogy
Homology is a structure that is similar in related species
Analogy are structures that function the same but due to similar environment pressure, can occur in two different species that are unrelated like dolphins and sharks
Fossil record/carbon dating and Mutation clock
Mutation clock: Goes back in fossil records and sees the rate of genetic mutation. The fewer mutations something has, the older it is and how long ago it diverged