biology exam revision (battleships cards)

feel free to add anything!

Which bases are purines?

adenine and guanine

which bases are pyrimidines?

cytosine, guanine and uracil

how many histone in a nucleus?

9 (8 on the DNA and histone one)

what is euchromatin?

regions of DNA where the nucleosome which are loosely bound

what is heterochromatin?

regions of DNA with nucleosomes which are tighty bound

where does transcription take place?

euchromatin

what is transcription?

the process in which DNA is used as a template to produce RNA (first stage of protein synthesis)

when did Chargaff falsify the tetra-nucelotide hypothesis?

early 1950’s

explain 5’ to 3’ direction on nucleic acid strands

designates the end of the DNA or RNA strand that has the fifth carbon in the sugar-ring of the deoxyribose or ribose at its terminus

what types of bonds are present in the backbone of DNA?

phosphodiester bonds and covalent bonds

what is a nucleotide made of?

phosphate group, pentose sugar (deoxyribose) and nitrogenous base

what is name and type of reaction that joins monomers?

polymerisation - condensation reaction

who was the scientist who discovered and extracted DNA?

Friedrich Miescher

difference between allopatric speciation and sympatric speciation

allopatric - different geographical locations - unable to reproduce with one another. sympatric - same geographical location but cannot reproduce with each other due to isolating mechanisms like behaviour and temporal isolation

what does density dependent mean?

impacted by size/density of the population - e.g. natural disasters

give an example of sympatric speciation

Hawthorn maggot in North America - when apples were domesticated, some maggots started to use them as food sources. Therefore due to nature and the behaviours of maggots became too different for them to reproduce with one another and became their own speciations of maggots

what is an SNP (single nucleotide polymorphisms)

term used to describe the difference between single DNA nucleotides.

3 types of horizontal gene transfer

conjugation, transformation, transaction

uses of SNPs are:

DNA testing for genealogical companies, forensic DNA testing, paternity testing

what is the biological species concept?

States that a group of organisms can be defined as a species IF they are able to produce fertile offspring.

exceptions to the biological species concept are

bacteria (due to horizontal transfer) and hybrid animals

what is a species?

a group of organisms that can produce fertile offspring with one another

what is the role of complementary base pairing?

stabilises the structure and enables DNA replication to be accurate

where on a sugar carbon does the DNA polymerase attatch to?

3’ OH

what is the difference in the sugars of DNA and RNA

RNA has ribose sugar - DNA has deoxyribose sugar. This indicates that RNA has an extra oxygen on the second carbon.

How many bonds are between Adenine and Thymine

2 hydrogen bonds

Which molecules contain ribose sugars?

RNA

reasons to why organisms are NOT considered living organisms

do NOT metabolise, do NOT use homeostasis, do NOT grow, need another organism to reproduce (host), do NOT excrete waste, do NOT need nutrition

2 methods of cell replication for eukaryotes

mitosis and meiosis

what is one quality that the mitochondria and chloroplast BOTH possess

double membrane, their own DNA

name an organelle ONLY found in plant cells

chloroplasts

describe the structure of a phospholipid

amphipathic molecule - hydrophilic head and hydrophobic tail

outline the differences between prokaryote and eukaryote cells?

prokaryotes - naked DNA, plasmid, 70s ribosomes, DNA nucleoid

eukaryotes - DNA wrapped around in nucleus, 80s, ribosomes

what is binary fission?

asexual reproduction which an organism divides into two, each part carrying one cope of genetic material.

what is the size of ribosome in prokaryotes

70s

the 3 principles of cell theory

1. all organisms are composed of one or more cells

2. cells are the most basic unit of structure of organisms

3. all cells come from pre-existing cells

define the ‘Goldilocks’ zone

the habitable zone where it is ‘not too hot or too cold’ refers to the orbital distance from a star hat will resets in the presence of liquid water.

why is water polar?

due to the unequal sharing of electrons (the electronegativity of O is more than H so the electrons will be more attracted to the O)

how does water’s polarity influence its solvent properties

it will allow other polar substance dissolve as it is a polar solute

why does water have a high specific heat capacity?

hydrogen bonds will need to be broken to raise the temperature

what is cohesion a result of?

it occurs as a result of water being a polar molecule

complete the substance: all substances that dissolve water are…

hydrophilic

what is the order of the hierarchy of taxonomy?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

what is a clade?

a group of organisms that descend from a common ancestor

what are 3 parts of a cladogram

1. root - represents most ancient common ancestor

2. node - represents a hypothetical common ancestor

3. terminal brunch - represents an existing species

what are cladistics

they are a way to work out the evolutionary relationships between species based on shared traits and genetic evidence

findings of Miller-Urey

a primordial soup which contained basic organic monomers (amino acids, lipids and carbohydrates)

8 requirements for life

Metabolism, Response, Homeostasis, Movement, Growth, Excretion, Reproduction, Nutrition

4 hypotheses for the origin of cells NOT including the ‘RNA first’ hypothesis

1. miller-urey

2. metabolism ‘first’

3. ‘sulfur world’

4. ‘lipid world’

outline the main features of EARLY earth’s atmosphere

lacked free oxygen, NO ozone layer present, majority of the atmosphere consisted of Methane and Ammonia gases

state the gases used in Miller-Urey experiments

methane, ammonia, water vapour, hydrogen gas

state the purpose of catalysts

LOWERS the activation energy to speed up the rate of reaction

describe what the Miller-Urey experiment helped to prove

non-living synthesis organic molecule was possible in the conditions existing on early Earth

state the biological catalyst found in our bodies and cells

enzymes

outline the 5 details for the spontaneous origin for cells

1. synthesis of simple organic molecules

2. catalysis - acceleration of chemical reactions

3. self -assembly: Larger organic molecules including RNA and phospholipids were assembled from smaller molecules

4. self replication: Some of these molecules, including RNA were able to self-replicate.

5. compartmentalisation: Formation of a membrane-bound compartment (the cell surface membrane) allowed the internal chemistry of the cell to become different from that outside the compartment.

components of miller-urey experiment

• closed system set up containing water (simulates the ocean)

• gas inlet to add to reducing the gases

• electrical sparks to simulate electrical storms

describe the aim of Hershey and Chase

to determine whether DNA or protein make up the genetic material

what is allopatric speciaton

is essentially geographical isolation - when a species is split into 2 due to geographical barriers preventing them to exchange genetic material

what are atypical cells

cells that do not fit into our classification of cells or living things

what are the two main ways of classifyinfg species and which is more accurate?

physical traits and molecular sequences. molecular sequencing is more accurate as scientists can see the DNA differences

how do black throated loons utilise thermal conductivity

oiled exterior feathers exude water, insulated by air trapped down by feathers

the characteristic of LUCA

• existed between 2.5-3.5 billion year ago

• existed in alkaline hydrothermal vents, which were rich in hydrogen and dissolved minerals like sulfur, methane and iron

• was anaerobic - oxygen was absent

• antotrophic

what does LUCA stand for

Last Universal Common Ancestor

define specific heat capacity

Amount of energy needed to RAISE the temperature of one unit of mass of a substance by one unity of temperature.

what is molecular phylogeny

way to proving the common origin of life via comparative analysis of DNA bases sequences, RNA, amino acids and proteins

why is the classification of organisms needed?

• grouping similar ideas helps to organise them

• common language for better communication

• to easily find and categorise things (efficiency)

• further research by identifying patterns

explain the electronegativity of water

• electronegativity is the ability of an atom to attract a pair of electrons in a bond

• oxygen have a stronger electronegativity than hydrogen and thus the electrons will spend more time around the oxygen atom than the hydrogen atom

• oxygen has a partial negative charge whereas hydrogen has a partial positive change