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Biology Y12 > Genetic Information, Variation And Relationships Between Organisms > Flashcards

Genetic Information, Variation And Relationships Between Organisms Flashcards

(71 cards)

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1
Q

Genome

A

Complete set of genes in a cell

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2
Q

Proteome

A

Full range of proteins produced by the genome

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3
Q

Codon

A

3 bases that code for an amino acid

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4
Q

Importance of meiosis

A

Necessary to halve the number of chromosomes going into the sex cells

So offspring has genes from each parent

So genetic variation

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5
Q

First meiotic division

A

Chromosomes replicate forming 2 chromatids joined together by a centromere

Homologous chromosomes line up, crossing over occurs, homologous chromosomes separate

Doesn’t happen in an order - “independent segregation of chromosomes”

2 diploid cells produced

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6
Q

Second meiotic division

A

Sister chromatids separate

4 haploid cells are formed, each with 23 single chromosomes

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7
Q

Variation in crossing over

A

When homologous chromosomes are lined up together during meiosis 1, they wrap around eachother and sections can be exchanged

Breaking and re-joining of DNA is known as recombination

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8
Q

Transcription

A

Double helical structure of DNA is unwound as hydrogen bonds between bases are broken

One DNA strand acts as a template

RNA nucleotides align by complementary base pairing

In RNA uracil pairs with adenine

RNA polymerase joins RNA nucleotides by phosphodiester bonds

pre-mRNA is spliced to form mRNA

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9
Q

Translation

A

mRNA attached to ribosomes at the start codon

tRNA anticodons bind to complementary codons which brings a specific amino acid

Amino acids joined by peptide bonds with the use of ATP

tRNA released

Ribosomes moves along mRNA to form the polypeptide

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10
Q

Classification definition

A

The organisation of living organisms into groups

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11
Q

Species definition

A

A group of organisms that have similar characteristics and are capable of interbreeding to produce fertile offspring

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12
Q

D
K
P
C
O
F
G
S

A

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

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13
Q

4 reasons why is it difficult to define species

A

Species are not fixed, they change over time

Some species are sterile

Considerable variation between species exists

Some rarely reproduce sexually

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14
Q

4 reasons why courtship behaviour is important

A
  1. So animals can recognise members of the same species to ensure fertile offspring
  2. To identify a mate that is capable of breeding - needs to be fertile, sexually mature
  3. Form a pair bond
  4. Synchronisation of mating to ensure mating occurs when there is maximum probability of the sperm & egg meeting and survival of offspring
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15
Q

Artificial classification

A

Divides organisms according to differences e.g. size, leaf shape, colour

These are analogous characteristics as they have the same function but not evolutionary origins

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16
Q

Phylogenic classification

A

Based on evolutionary relationships between organisms and their ancestors

Classifies species into groups using shared features from ancestors

Arranges groups into hierachy

Groups consist of larger groups but don’t overlap

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17
Q

Taxonomy definition

A

The theory/practice of classification

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18
Q

Taxon meaning

A

Group within phylogenic classification

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19
Q

Organising groups of species:

Bacteria

A

Absence of membrane-bound organelles

Cell walls of murein

Single loop of DNA made up of nucleic acids and no histones

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20
Q

Organising groups of species:

Archaea

A

No murein in their cell walls

Genes and protein synthesis are more similar to eukaryotes

More complex form of RNA polymerase

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21
Q

Organising groups of species:

Eukarya

A

Membrane-bound organelles

Ribosomes are larger (80s) than bacteria and archaea (70s)

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22
Q

Species diversity

A

Number of species and number of individuals within species in a community

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23
Q

Biodiversity

A

All the variety of organisms in the living world

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24
Q

Species richness

A

Number of different species

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25
3 human activities than have a direct impact on species diversity
1. Removal of hedgerows and woodland 2. Filling in ponds and draining marsh/wetlands 3. Creating monocultures
26
3 human activities than have an indirect impact on species diversity
1. Use of pesticides and inorganic fertilisers 2. No crop rotation and lack of intercropping 3. Escape of effluent from silage stores and slurry tanks into water courses
27
4 human activities than have a conservative impact on species diversity
1. Leave wet fields rather than draining them 2. Plant native trees where species diversity is low 3. Reduce use of pesticides 4. Use organic fertilisers
28
Quantitive Investigation of Variation: Sampling (stative&mobile organisms)
Static organisms: plants & some animals, use quadrats and transects Mobile organisms: animals, mark release recapture technique
29
Quantitive Investigation of Variation: Random sampling
Grid an area Use RNG to give coordinates Take samples at coordinates
30
4 ways abundance can be measured
Density Frequency Percentage cover A scaling measure
31
Genetic diversity within or between species can be made by comparing what 4 things?
1. Frequency of measurable/observable characteristics 2. Base sequence of DNA 3. Base sequence of mRNA 4. Amino acid sequence of the proteins encoded by DNA and mRNA
32
Comparing observable characteristics Use Limitation
Each observable characteristic is determined by the gene The variety within a characteristic depends on the number and variety of alleles of that gene 1. Many characteristics are continuous, not discrete, and therefore polygenic 2. e.g. Height is determined by a number of genes but diet can influence the height of an individual, so this method is limited in use
33
Comparing DNA base sequences 1. Why have we been enabled to do this 2. Example 3. How? 4. Advantage
1. Due to scientific advances there is more evidence to determine evolutionary relationships between organisms 2. e.g. DNA differences from measurable/observable characteristics has now been replaced by direct investigation of DNA sequences 3. Base sequences of an organism are done by automatic machines and analysed by a computer Each nucleotide base is tagged with a different coloured dye Analysis of the coloured bands allows comparison between/within species 4. This allows the evolutionary relationships between species to be identified
34
Comparing mRNA base sequences
Base sequences on mRNA are complementary to those of the DNA strand from which they were made Genetic diversity can be measured by comparing the base sequence on mRNA
35
Comparing amino acid sequence in proteins
Since amino acid structure determined by mRNA which is determined by DNA - genetic diversity can be measured by comparing amino acid sequence Comparing the similarities and differences in the amino acid sequence of the same protein in different organisms The fewer differences between the amino acids, the closer the relationship between the two species and the more recently they shared a common ancestor
36
Ecology definition
The study of the inter-relationships between organisms and their environment
37
Environment definition
Including both biotic and abiotic factors
38
Ecosystem definition
Dynamic system that make up a community and all the non-living factors of its environment
39
Population definition
Each species is made up of a group of individuals
40
Carrying capacity
The certain size of population of a species that the ecosystem can support
41
Community
All the populations of different species living and interacting
42
Microhabitat
Within each habitat there are smaller units, each with their own microhabitat e.g. Mud at the bottom of the stream may be the microhabitat for a bloodworm
43
Ecological niche
Where an organism lives and its role within the environment
44
Biotic
Living part of the environment
45
Abiotic
Non-living part of the environment
46
Competitive inclusion principle
If two species try to occupy the same niche, there is competition and only one species will win
47
Population growth rate equation
Population growth rate= Crude birth rate minus crude death rate
48
Crude death rate equation
Crude death rate= number of deaths in one year divided by total population of that year
49
Population growth equation
Population growth= (births and immigration) minus (deaths and emigration)
50
Crude birth rate equation
Crude birth rate= number of births in one year divided by total population of that year
51
4 factors affecting birth rates
1. Economic conditions 2. Cultural & religious backgrounds 3. Political factors 4. Birth control
52
8 factors affecting death rates
1. Age profile 2. Life expectancy at birth 3. Food supply 4. Medical care 5. Natural disasters 6. Safe drinking water 7. War 8. Effective sanitation
53
Intraspecifc competition
Individuals of the same species compete with one another for resources such as food, water, breeding sizes, it is the availability of such resources that determines the size of a population
54
Interspecific competition
Individuals of different species compete for resources such as food, light, water When populations of two species are in competition, one will normally have a competitive advantage over the other The population of this species will gradually increase in size while the other will diminish If conditions remain the same, this will lead to the complete removal of one species, this is known as the competitive exclusion principle
55
Effect of predator-prey relationships on population size
Predators eat their prey, thereby reducing the population of prey With fewer prey available, the predators are in greater intraspecific compettion Predator population is reduced as some individuals will be unable to obtain enough prey for their survival or to reproduce With fewer predators left, fewer prey are eaten and more survive and are able to reproduce Prey population increases With more prey now available, predator population increases
56
Importance of disease and climactic factors in populations
Periodic population crashes are important in evolution as there is a selection pressure which means that those individuals who are able to escape predators/withstand disease/an adverse climate are more likely to survive and reproduce
57
Mark-Release-Recapture
1. Capture random sample, mark each animal with non-toxic marker, record number 2. Marked animals are released and mix with the unmarked individuals for a set period of time 3. Sample the population again, count and record the total number of animals and the number of marked animals
58
Lincoln Index
Number of first sample x number in second sample divided by marked in second sample
59
Assumptions of the mark-release-recapture
Proportion of marked:unmarked individuals in the second sample is the same as the proportion of marked:unmarked in the whole population Marked individuals have had time to mix freely No emigration/immigration Population must be stable (no births/deaths) Mark must be permanent and non-toxic
60
Succession definition
The change in an ecosystem over time allowing new species to grow
61
Example of primary succession
Plants grow where they never have before
62
Example of secondary succession
Plants re-grow where there has been a previous population
63
How a primary succession occurs
Pioneer species reproduces asexually Mass seed/spore production Rapid germination Tolerant to extreme conditions
64
Secondary colonisers
E.g. mosses, ferns, rocks have broken down, dead lichens have changed the abiotic conditions
65
Tertiary colonisers
E.g. grasses, flowers, increasing soil levels, nutrients, organic matter, water content, abiotic factors change
66
Shrubland
E.g. shrubs, small trees, food sources expanding, wider food chains and webs supported, biotic changes
67
Climax community
Balanced equilibrium of species, many species, high biodiversity, stable
68
Diagram of succession
Barren land -> Primary colonisers -> Secondary colonisers -> Tertiary Colonisers -> Shrublands -> Climax community
69
Mark scheme answer to how succession occurs
Colonisation by pioneer species Change in environment Enables other species to colonise Change in biodiversity Stability increases Climax community
70
Variation in independent segregation
Occurs during meiosis 1 when homologous chromosomes line up after replication When they arrange themselves in a line they do so at random Combination of chromosomes that goes into the daughter cells is at random
71
How to identify meiosis in a life cycle?
2n -> n n = meiosis state diploid -> haploid

Biology Y12 (9 decks)

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