Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A Level Biology (SNAB) > Topic 4 > Flashcards

Topic 4 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is a niche?

A

= The role and position of a species in an environment

= The precise role of an organism in an environment

  • Two species sharing the same habitat will tend to not be in competition w/ each other as they will have a different ecological niche
  • If two species live in the same habitat and have the same ecological niche the better adapted organism will outcompete the other and exclude it from the habitat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a habitat?

A

Habitat = the particular place where a community of organisms is found

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a population?

A
  • a group of individuals belonging to one species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a community?

A
  • all the living organisms in an area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a species?

A

= a group of similar organisms which can breed to produce fertile offspring

= a group of organisms w/ similar morphology, physiology, and behaviour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are some molecular techniques to determine a species?

A
  • DNA
  • Morphology
  • Physiology
  • Behaviour
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are behavioural adaptations?

A

Behavioural = acts or reactions that an organism, individual or system produces in response to a particular circumstance

  • The way it interacts w/ its environment and organisms present, such as, feeding, territory, courtship, escaping predators
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are physiological adaptations?

A

Physiological = the functions and activities of life or of living matter and of the physical and chemical phenomena involved

  • Body chemistry and qualities that help it explore its niche, ie. temp control, camouflage, reproductive strategy, digestion, chemical signalling, venom
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are anatomical adaptations?

A

Anatomical = the bodily structure of an organism or of any of its parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an adaptation?

A

Adaptation = a process by which an animal or plant species becomes fitted to its environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The ability of a new population to adapt to new environments depends on…?

A
  • The strength of the selective pressure
  • Size of the gene pool and mutation role
  • The reproductive rate of the organism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the dynamics of adaptation?

A
  • No organisms will be perfectly adapted to its environment
  • Environmental change has a time lag
  • Mutations occur all the time naturally

The niche
- Avoids competition
- Interdependence = vulnerable

  • Adaptable species are always in competition but less vulnerable to change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is co-evolution?

A

Co-evolution = when two or more species reciprocally affect each other’s evolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is interdependence?

A

Interdependence = the dependence that two or more things have on each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is natural selection?

A

Natural selection = the process in nature by which organisms that are better adapted to their environment tend to survive longer and transmit more of their genetics and characteristics to succeeding generations than those less well adapted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the assumptions made in order for the Hardy-weinburg equation?

A
  • Large population = everything is equally represented
  • Mating is random = doesn’t influence the changing population
  • No selective disadvantage/ advantage for any genotype
  • No mutations, migration or genetic drift
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is genetic drift?

A

Genetic drift = the change in frequency of an existing gene variant (allele) in a population due to random sampling of organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What can the Hardy-weinburg equation be used to show?

A
  • See phenotype/ genotype
  • To know how many sufferers/ carriers there are
  • To see if assumptions are true
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The Hardy-Weinburg Equation

A

We can find by seeing who suffers from the disease
p can be found by 1 - q = p
Once we have p and q we can find out how many carriers of a disease there are

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the sources of variation? - Reproductive isolation

A
  • Random assortment
  • Crossing over
  • Which sperm reaches the egg
  • Mate selection/ random/ fertilisation

Mutations
- Gene (point) mutations
- Chromosome mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is biodiversity?

A

= refers to the variance and variability of life on earth

= the number and variety of different organisms found in a specified area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why should we protect biodiversity?

A
  • Ensure a stable atmosphere of gases as a source of Oշ
  • Is the foundation of human health and welfare
  • Essential to the security of our food sources
  • Inv. in many medicines
  • Biotechnology - value of genetic material in - plants and animals
  • Large diversity means less impact from other species
  • Needed for long-term sustainability and mitigation of climate change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is conservation?

A

Conservation = an ethic of resource use, allocation and protection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is an endangered species?

A

Endangered = a species seriously at risk of extinction

  • Conservation management: successful if the species is able to retain enough genetic diversity to survive minor environmental changes in their natural habitat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the order of classification?

A

K - kingdom - keep (plants/ animals/ fungi/ prokaryotes/ protists) (PP FAB)

P - phylum - parts (mammals/ reptiles/ fish/ amphibians/ birds) (MR FAB)

C - class - clean

O - order - or

F - family - forget

G - genus - good

S - species - sex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is Archaea? - Three Domain Theory

A

Archaea = look like conventional bacteria on the outside but work in different ways

  • Ribosomal RNA (rRNA)- since ribosomes have a role in protein synthesis they don’t change during evolution
  • Membranes composed of hydrocarbon chains attached to glycerol by ester linkages
  • Mutations will impair/ change their functions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is bacteria - Three Domain Theory

A

Bacteria = prokaryotic cells that are common in human daily life

  • Membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages
  • Has unique rRNA to the bacteria indicated by the presence of molecular regions different from rRNA of Archaea and Eukarya
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are Eukaryotes - Three Domain Theory

A

Eukaryotes = have eukaryotic cells

  • Membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages
  • Contain rRNA unique to eukarya
    Four kingdoms: protista/ fungi/ plantae/ animalia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the degenerate code?

A

Degenerate code = a code in which several code words have the same meaning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the differences in ribosomes?

A

Prokaryotes and archaea = 70S
Eukaryotes = 80S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are some ways to evaluate scientific ideas?

A
  • It is peer reviewed by scientists who specialise in the area
  • Publish in a scientific journal
  • Other scientists repeat the experiment to hopefully get similar results
  • Other scientists use the theory to make new predictions and experiments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is species diversity?

A

Species diversity = the no of different species and the abundance of each species in an area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is genetic diversity?

A

Genetic diversity = the variation of alleles w/n a species of a population of a species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is ecosystem diversity?

A

Ecosystem diversity = the variety of alleles w/n an area
- This will result in a higher species diversity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How can you measure diversity?

A

Quadrats/ transects w/ low growing plants
Pooters for insects (a straw to suck up the insects)

Pitfall traps for insects (generally nocturnal ones)

Sweep nets (like ones used for butterflies)
Kick sampling (net underwater and kicking river bed)

Capture/ recapture technique = capturing animals, marking them in a way that doesn’t affect survival chances, catch them again to examine how many are marked

36
Q

What is the heterozygosity index?

A

Heterozygosity index = the proportion of genes which are present in heterozygous form

    Number of heterozygotes -------------------------------------------------- No. of individuals in the population

The higher the number the larger the genetic diversity = more chance of survival

37
Q

What is species evenness?

A

Species evenness = a measure of the relative abundance of the different species making up the richness of an area

  • How even is the distribution
38
Q

What is species richness?

A

Species richness = no of species per sample/ area

  • The more species present the richer the sample
  • More money = richer, more species = richer
39
Q

What is taxic richness?

A

Taxic richness =measures genetic diversity by using the relationship b/w organisms w/n an area

  • The less closely related, the higher the score
40
Q

What are biodiversity hotspots?

A

Biodiversity hotspots = an area w/ a particularly high plant biodiversity,

Eg. Mediterranean basin holds 10 % of earth’s plant species

41
Q

What is sample size rarity?

A

Sample-size rarity = a measure of how common an organism is

  • The less common the greater the weighting
42
Q

What is germinating?

A

Germinate = a seed/ spore begins to grow and put out shoots after a period of dormancy

43
Q

What are tonoplasts?

A

Tonoplasts = a cytoplasmic membrane surrounding the vacuole

44
Q

What are amyloplasts?

A

Amyloplasts = non- pigmented organelle where starch is stored

45
Q

What is molecular phylogeny?

A

Molecular phylogeny = analysis of the structures of many different chemicals and genes to identify the interrelationships b/w groups of organisms

46
Q

What is celluose?

A

Cellulose = made up of beta glucose

  • Produces strong cell walls from cellulose
  • Polymer of sugar molecules
  • Can build columns and tubes w/ it
    Stiffen these cells w/ another polymer called lignin
47
Q

What is starch?

A

Starch = made up of amylose and amylopectin = made up of alpha glucose

  • Test for starch is iodine (turns it blue/ violet)
48
Q

How does the formation of a beta polymer work?

A
  • Condensation reaction b/w OH groups, 1st + 4th carbon, forms 1-4 glycosidic bonds
  • Forms a long unbranched molecule
  • Molecules join at 180 to each other
49
Q

What is microfibril?

A

Cellulose chain contains 1,000 to 10,000 glucose units

H bonds b/w neighbouring cellulose chains form bundles = microfibrils

Microfibrils ‘glued’ together w/ branched polysaccharides called hemicelluloses and pectins (amylose and amylopectin)

Pectin acts as a cement in the middle lamella, joining cells together

50
Q

What is the epidermis?

A

Epidermis = single layer covering plant

51
Q

What is vascular tissue?

A

Vascular tissue = inv. in transport (xylem + phloem)

  • NB sclerenchyma fibres surround the vascular bundles (around phloem)
  • They harden/ strengthen the vascular bundles
  • The cambium separates the xylem and phloem
52
Q

What are ground tissues?

A

Ground tissue = contains cells specialised for photosynthesis, storage + support

53
Q

Water and Mineral transport

A
  • Water in xylem is pulled upwards by the constant movement of water into the leaf caused by transpiration
  • Removal of water at top of xylem causes a gradient in hydrostatic pressure, w/ lower pressure at the top
  • Water moves down pressure gradient continuously (transpiration stream)
  • Cohesion drags it up, adhesion keeps it from falling
54
Q

What is the movement of water and ions?

A

Water: soil→root hair cells→xylem
- Osmosis - moves down osmotic gradient

Ions: soil→root hair cells→xylem
- Active transport

55
Q

What is cohesion?

A

Cohesion = the attraction of molecules to other molecules of the same kind

56
Q

What is adhesion?

A

Adhesion = the attraction of molecules to dissimilar particles or surfaces

57
Q

What is the xylem?

A

Xylem = vascular tissue responsible for the conduction of water and nutrients from the roots up the stem to the leaves

58
Q

What is the phloem?

A

Phloem = vascular tissue which conducts sugars and ions downwards from the leaves

59
Q

What is transporation?

A

Transpiration = the process where plants absorb water through the roots that then evaporates through pores in their leaves, basically water movement in the xylem

60
Q

What is the stomata?

A

Stomata = tiny openings to allow plants to exchange the gases necessary cellular processes

61
Q

What is sclerenchyma?

A

Sclerenchyma = support tissue composed of any of various kinds of hardwood, fibres and sclereids

62
Q

What is plasmodesmata?

A

Plasmodesmata = a narrow thread of cytoplasm that passes through cell walls of adjacent cells, allows communication b/w them

63
Q

What is the process of water transport?

A

Evaporation of water from the cells in the substomatal cavity of leaves provides the force needed to draw water up a plant

The channels b/w the cellulose microfibrils in the cell act as capillaries

Capillaries can draw water up them by capillary action

Capillary action is caused by surface tension
As water evaporates, it is replaced by capillary action

The capillaries in the cell walls of leaves produce a pull on the water behind them

The pull then draws water from the xylem and up the stem

This stream of water is the transpiration stream

64
Q

What is translocation?

A

Translocation = the movement of organic solutes from source to sink through the phloem by means of mass flow

  • Sugar movement in phloem
65
Q

What are plant fibres?

A

Plant fibres = long tubes of plant cells

66
Q

Why are plant fibres strong?

A
  • They’re strong so can be used for ropes or fabrics

Strong b/c of the arrangement of cellulose microfibrils in the cell wall
- A net-like arrangement
- Microfibrils are strong
- Strong b/c of secondary thickening of cell walls

  • Forms b/w cell wall and cell membrane
  • It is thicker and made more of lignin
  • Lignin is a woody substance making them stronger
67
Q

Tensile strength of plant fibres experiment

A
  1. Extract a plant fibre→to use as a test subject→insects on plant = infection
  2. Attach the fibre to a clamp stand→to keep it steady→heavy (feet)
  3. Measure the length of the plant fibre→so length can be taken into account
  4. Add a weight to the end of the plant fibre→to see if it can hold it→heavy (feet)
  5. Keep adding weights until it breaks→to see how much it takes to break→heavy
  6. Record the weight the plant fibre breaks at→for validity→weights may go everywhere
  7. Repeat the experiment with the same type and length of plant fibre→for reliability
  8. Calculate a mean and draw an appropriate graph→for reliability
68
Q

What are some sustainable uses of plant fibres?

A
  • Ropes and fabrics can be made instead of using plastic (from oil)
  • Meaning less fossil fuels are used up and crops can be regrown
  • Products are then biodegradable (broken down by microbes)
  • They are easier to grow and process than oil so its cheaper
69
Q

What are the sustainable uses of starch?

A
  • It can replace plastic made from oil, they’re then bioplastics
  • It can replace vehicle fuel, e.g bioethanol
  • Meaning less fossil fuels are used up and crops can be regrown
70
Q

Water and inorganic ions

A
  • Water is needed for photosynthesis, to transport molecules, maintain structural rigidity (from pressure), and regulates temperature
  • Magnesium ions for production of chlorophyll for photosynthesis
  • Nitrate ions for DNA, protein, chlorophyll production, for plant growth, fruit and seed production
  • Calcium ions for cell walls for plant growth
71
Q

Plant mineral deficiencies experiment

A
  1. Make 5 mixtures: all nutrients, no nitrogen, no magnesium, no calcium and then deionised water→to compare against→liquids
  2. Then split the mixtures up into three test tubes each→for validity→liquids
  3. Measure the masses of 9 germinated seeds of the same plant, e.g mung beans→to use as test subjects→diseases
  4. Then place the seeds’ roots in the mixtures with the seeds out of the liquid using cling film→to represent the ground→glass
  5. Cover the outside of the test tube w/ foil→to prevent light entering and algae growth
  6. Then place all the test tubes near the same light source and leave for two weeks→to allow for plant growth→light = eyes // burn
  7. Every day check if the mixtures need topping up to keep the roots suspended→for plant growth
  8. Carefully remove each plant and blot dry→to not affect mass // for validity
  9. Measure and record the masses of the plants→to compare
  10. Calculate the mean change from the results→for reliability
72
Q

What are the drug testing phases?

A
  1. Testing on a small group of healthy individuals to find a safe dosage and any side effects
  2. Tested on a large group of patients to see how well it works
  3. Compared to existing treatments using a large sample size
73
Q

What is a placebo?

A

Placebos = an inactive substance that looks like the drug but doesn’t do anything

Phase 2
- Tests if the drug actually works and its not the people saying/ believing they’re better

74
Q

What is a double blind study?

A

Double Blind Study = neither the patients nor doctors know who has the drug or placebo

Phase 2 and 3
- This reduces bias as attitudes can’t change the results

75
Q

How to test bacterial growth?

A

To test it, the conditions have to be right for bacteria to survive and reproduce

  • Nutrients are needed to respire and grow
  • They may need oxygen for aerobic respiration
  • The temp and pH of the environment can not be too high or low
  • It affects enzyme activity meaning metabolic processes can’t occur normally
76
Q

Antimicrobial properties of plants experiment

A
  1. Prepare an agar plate and transfer the bacteria using a sterile pipette→to place in a controlled environment // prevent cross-contamination→its bacteria
  2. Spread the bacteria around the plate using a sterile plastic spreader→for a large SA // to prevent cross-contamination→seriously, its bacteria
  3. Cover the plate w/ lid→to keep it contained→back to the point it’s bacteria
  4. Dry and grind each plant you want to test and soak in ethanol→to use as test subjects // to sterilise→ethanol = slip/ flammable/ eyes
  5. Filter the ethanol off and using sterile forceps dip equally sized sterile absorbent paper in the plant extracts→so the ethanol doesn’t affect it→ethanol
  6. Leave for one hour→to absorb the plant extracts→liquids // glass
  7. Place the discs on the agar plate with another equally sized disc of just ethanol→control group→ethanol
  8. Tape the lid shut, invert and incubate at 25°C for 48 hours→to allow for it to kill the bacteria
  9. Then remove the lid and make 4 radius measurements of each clear zone and calculate an average→to measure and compare→it’s still bacteria
  10. Repeat the experiment and create an average→for reliability and validity
77
Q

What are the purposes of Zoos and seed banks?

A

Purpose = conserve endangered species of plant and animals

  • Extinction of a species/ loss of genetic diversity w/n a species causes reduction in global diversity
  • Some are already extinct (dodo) and some are endangered
78
Q

What are seed banks?

A
  • Store lots of seeds from different species of plants, esp. endangered ones
  • Conserve biodiversity and genetic diversity through storing them
  • If a plant becomes extinct, the seeds can be used to regrow them
79
Q

What is the storing process of seed banks?

A
  1. Check they have a permit to store the plant
  2. Dry out the plant
  3. Move to the dry room, which is at 15°C, for 6 months
  4. So only a 5% moisture is left, ↓metabolism
    Clean them from the rest of plant material, to prevent contamination
  5. Put them through a vacuum to remove weak seeds
  6. Xray them to make sure they have a healthy embryo
  7. Dry them out again
  8. Seal them and store them at -20°C
  9. Every 10 years take some seeds out to see germination success
  10. It has to be above 75% for the seeds not to be replaced
80
Q

What are the advantages of seed banks?

A
  • Cheaper than fully grown plant
  • Larger numbers w/ less space
  • Less labour required
  • Can be stored in any cool dry place
  • Less likely to be damaged from disease, natural disasters or vandalism
81
Q

What are the disadvantages of seed banks?

A

Testing viability is expensive and time consuming

  • Too expensive to store and test all types of seeds
  • Can be difficult to collect seeds from remote locations
82
Q

What are zoos?

A
  • They use captive breeding programmes
  • Endangered or extinct in the wild can be bred together, e.g. pandas
  • This can help protect genetic diversity and global biodiversity
83
Q

What are the problems with zoos?

A
  • Animals may not be willing to breed outside of their habitats
  • There might not be enough animals of a species to breed successfully
  • Age, gender, health, siblings
  • Many people think it’s cruel to keep them in captivity
84
Q

What is reintroduction? (zoos and seed banks)

A
  • Once numbers have increased and the habitat is available they can reintroduced into the wild
  • Can bring species back from the brink of extinction
  • Can help other organisms who rely on these reintroduced organisms
  • Reintroducing plants helps restore habitats
85
Q

What are the problems with reintroduction?

A
  • They may bring new diseases harming other organisms
  • The organisms may not be able to survive in the wild successfully
  • E.g open season (the film but w/ a sad ending)
86
Q

How do seed banks contribute to scientific research?

A
  • Can study how plant species are grown
  • Can grow endangered plants useful for new crops/ materials
  • Protecting the plants already in the wild
  • Can provide knowledge to local people on how to protect plants
  • E.g the Millenium Seed Bank Project
  • But limited to the small number of seeds that are stored
87
Q

How do zoos contribute to scientific research?

A
  • Increases knowledge on behaviour, physiology and nutritional needs
    Contributing to conservation methods

Can carry out research studies not possible in the wild
- E.g. nutritional or reproductive studies

Educates the rest of the world so they are more interested
- More willing to want the animals to be protected

Can educate local people on why they shouldn’t hunt/ kill them
- E.g. learning elephants don’t like tomatoes in their eyes so tomato bombs are being used to deter elephants entering villages

  • Though animals in captivity may act differently to those in the wild

A Level Biology (SNAB) (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions