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Biology > Topic 4 > Flashcards

Topic 4 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Biodiversity

A

the variety of living organisms within a particular habitat

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2
Q

species richness

A

the number of different species in a habitat

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3
Q

species evenness

A

abundance (number of individuals) of different species in a community- percentage ratio of species (how even?)

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4
Q

heterozygosity index?

A
  • measure of genetic biodiversity
  • H= number of heterozygotes / number of individuals in the population
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5
Q

Simpsons diversity index:

A

N(N-1) / sum of n(n-1)
- N= total number of individuals
- n= number of individuals of each species
- the higher the number, the greater the biodiversity

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6
Q

endemism:

A

the confinement of a particular species, genus or group of organisms to a particular area

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7
Q

ecological niche?

A

the way an organism exploits its environment/ role of the organism in its environment

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8
Q

natural selection

A

the process where fitter individuals who are better adapted to the environment’s selection pressure and survive and reproduce to pass on their advantageous alleles.

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9
Q

anatomical adaptation?

A

physical adaptations, either external, or internal (we can see when we observe/ dissect the organism) e.g. long loops of Henle which allow desert mammals to produce concentrated urine and minimise water loss.

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10
Q

Behavioural adaptations:

A

changes in behaviour which improve the organisms chance of survival e.g. mating calls, mimicry

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11
Q

Physiological adaptations

A

are processes that increase an organisms chance of survival e.g. regulation of blood flow through skin or more myoglobin (e.g. in whales)

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12
Q

evolution

A

the process by which the frequency of alleles in a gene pool changes over time as a result of natural selection.

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13
Q

Process of evolution via natural selection:

A
  • a variety of phenotypes exist within a population due to mutation
  • an environmental change occurs changing the selection pressure
  • some individuals possess advantageous alleles which give them a selective advantage and allow them to survive and reproduce
  • the advantageous alleles are passed onto the offspring
  • over time, the frequency of alleles in a population changes (evolution)
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14
Q

The hardy weinburg equation

A

p^2 +2pq+ q^2 =1
p + q=1
p= the frequency of the dominant allele
q the frequency of the recessive allele
p^2= frequency of homozygous dominant alleles
q^2 = frequency of homozygous recessive alleles
2pq= frequency of heterozygous

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15
Q

Asuumptions/ conditions for the Hardy Weinburg equation:

A
  • there are no mutations in a population
  • large population
  • random matinf
  • isolated population
  • no selection pressure
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16
Q

species?

A

organisms that can interbreed to produce fertile offspring

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17
Q

allopatric speciatioN:

A

speciation in groups of organisms that are geographically isolated

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18
Q

speciation

A

if two populations become reproductively isolated, new species will arise due to the accumulation of different genetic information in populations ovcer time (due to diffeerent environments and selection pressures )

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19
Q

sympatric speciation:

A

in which they are isolated by other means, within the same area (e.g. different behaviours, temporal mating seasons, mechanical isolation (genes not compatible) etc.)

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20
Q

process of allopatric speciation:

A
  • there is variation in the gene pool
  • a geographical event causes the population to split
  • the two populations are genetically varied
  • different selection pressures
  • different mutations occur in different populations
  • advantageous alleled organisms survival and reproduce, passing on these alleles
  • over time, the frequency of alleles changes
  • the populations evolve in different ways according to their environment and genetic variation
  • results in two distinct species which are unable to interbreed to produce fertile offspring.
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21
Q

genetic bottleneck

A

where few individuals in a population surivive an event or change (e.g. disease, environmental change like habitat destruction), reducing the gene pool.

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22
Q

Founder effect:

A

where a small number of individuals create a new colony, geographicallyy isolated from the original- the gene pool for the new population is small.

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23
Q

classification:

A

a means of organising the variety of life based pon relationships between organisms using differences and similaritiess in phenotypes and genotypes.

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24
Q

kingdoms:

A

animals, plants, fungi, prooctista (/ protist), prokaryotic

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25
Q

within each kingdom, they can then be grouped further into …

A

phylum, class, order, family, genus and species

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26
Q

each organism is names according to the …. system.

A
  • binomial
    The first part of the name is the genus and the swcond part of the name is the species
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27
Q

three domains

A

eukaryotic: animals, plants, protists
archaea: ‘old bacteria’ (prokaryotic)
Bacteria: peptidoglycan cell wall, ‘true bacteria’ (prokaryotic)

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28
Q

what is the evidence for the domain system?

A
  1. Pioneered sequencing os bacterua RNA
  2. Archaea- don’t have peptidoglycan cell wall
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29
Q

The analysis of molecular differences in different organisms to determine the extent of their evolutionary relationship is known as …

A

molecular phylogeny

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30
Q

The scientific community evaluates the data in the following ways:

A
  • the findings are published in scientific journals and presented at scientific conferences
  • scientists then study the evidence in a process called peer review
31
Q

what is proteomics?

A

the study of proteins. DNA to RNA to AA sequences to proteins structure

32
Q

plant ultrastructure:

A

they are eukaryotic so have a nucleus and membrane- bound organelles.

33
Q

cell wall:

A

the cell wall is made up of the middle lamella, which is made of calcium peptate and holds adjacent cells together and cellulose microfibrils and microfibres

34
Q

plasmodesmata:

A

an extension of the the cytoplasm between the cell wall of adjacnet cells involved in the transport of substances between them

35
Q

pits:

A

thin sections of the cell wall whcih also allow communication between adjacent cells

36
Q

chloroplasts:

A

the site of photosynthesis. Theuy cpntain a sack of thylakoid membrabes called grana containing chlorophyll. The grana are connected by extensions of thylakoid membranes called lamellae. Grana are surrounded by a colourless fluid calles stroma which contains all the enzymes required for photosynthesis. Chloroplasts are bound by a double membrane calles the envelope

37
Q

amyloplasts:

A

organelles, surrounded by a double membrane, which contain amylopectin (starch)

38
Q

vacuole

A

conatins cell sap and is surrounded by a tonoplasy (single membrane). Provides the cell with strength and support

39
Q

carbohydrates:

A
  • molecules which consist of only carbon, hydrogen and oxygen.
  • long chains of sugar called saccharides
40
Q

how do monosaccharides join together?

A
  • glycosidic bond
  • condensation reaction
41
Q

cellulose:

A
  • component in cell walls in plants and is composed of long, unbranched chains of beta glucose which are joined by glycosidic bonds (1,4)
    -microfibres formed of microfibrils are strong helical threads which are made of long cellulose chains joined together by hydrogen bonds and they provide structural support in plants. The microfibrils are glued together with polysaccharide glue- hemicellulose and pectin ( make up the middle lamellae of adjacent plant cells)
  • are insoluble so do not affect osmotic potential
42
Q

Starch:

A
  • insoluble- no effect on water potential
  • alpha glucose
  • amylose- compact, spiral, unbranched and therefore easily stored.
  • amylopectin- branched- 1,4 and 1,6 glycosidic bonds. the branching enables efficient hydrolysis.
43
Q

xylem vessels:

A
  • transport water and minerals, as well as provide structural support.
  • they are long cylinders made of dead tissue with open ends.
  • thickened with a tough substance called lignin- impermeable to water therefore is waterproof.
  • have pits
44
Q

Phloem vessels:

A

are tubes made of living cells which are involved in translocation, which is the movement of food substances and nuitrients from leaves to storage organs.
- have plasmodesmata
- made of seive tubes, seive tube elements

45
Q

cambium cells:

A
  • between xylem and phloem are undifferentiated and able to specialise as the plant grows
46
Q

sclerenchyma fibres:

A

provide structural support. They are short structures made of dead cells with a hollow lumen and end walls. They are also thickened with lignin

47
Q

Why are plant fibres useful to humans?

A
  • they are a sustainable and renewable resource, as the plants extracted can be regrown
  • plant fibre products are biodegradable, as they can be broken down by microbes, as opposed to materials made from non-renewable resources such as oil based products
  • plant fibres are very strong and therefore can be used to make materials such as ropes and fabrics
  • starch can be used to make bioplastics and bioethanol, which is fuel.
48
Q

transpiration:

A
  • water moves up the xylem with ‘cohesion tension’ and ‘capillary action’.
  • cohesion to other water molecules, adhesion to xylem wall
  • lower pressure in roots driven by evapouration of water out of the leaves
  • water moves out of the xylem into mesophyll cells by osmosis
  • H20 diffuses into airspaces (lower water potential of mesophyll cells causes water to move in from adjacent cell)
  • water evapourates from stroma, lower conc. gradient.
49
Q

what is water important for?

A
  • maintains cell turgidity, supplies water for cell growth elongation, keeps plants cool on a hot day, transport of substances, thermoregulation
50
Q

what is a vascualr bundle made of?

A

phloem, xylem, sclerenchyma, cambium cells

51
Q

what does the vascular bundle look like in a root?

A
  • the xylem is in an x shape in the circular cross section.
  • the phloem has circluar blobs in the cavities of the x
52
Q

what does a vascular bundle look like in the stem?

A
  • looks like flower petals
  • xylem section closest to the centre
  • after xylem, there is the cambium
  • then the phloem
  • then the slerenchyma layer
53
Q

what does the vascular bundle look like in the leaf?

A
  • long shape similar shape to a relay neurone (blob in middle)
  • in the blob, there is a circular section containing the phloem and xylem, xylem is closer to the straight part of the leaf
54
Q

what are magnesium ions important for?

A
  • involved in chlorophyll production
55
Q

what do nitrate ions do?

A
  • supply nitrogen for making DNA, RNA, proteins and chlorophyll
56
Q

what do calcium ions do?

A
  • component of the plant cell wall- they form calcium pectate which makes up the middle lamellae in the cell wall
  • essential for plant growth
57
Q

William Withering’s digitalis soup experiment

A
  • he isolated the active ingredient from foxglove and then tested different doses on patients and recorded the finding s
58
Q

companion cells have…

A
  • large nucleus
  • desne cytoplasm
  • many mitochondria
59
Q

The meaning of cohesion in the cohesion-tension theory:

A

the concept that many of the same molecule stick together, in transpiration, it is water. This is because water is polar and therefore can form hydrogen bonds forming a column

60
Q

The meaning of tension in the cohesion- tension theory

A
  • a transpiration stream forms as water evapourates out of the stomata into the leaf causing a pressure differential, causing more water to be absorbed in the root hair cells by osmosis
61
Q

What is a source?

A

-provides assimilates for photosynthesis

62
Q

what is a sink?

A
  • uses assimilates for meristem cell activity and division
63
Q

Active loading:

A
  • sucrose is actively transported into the seive tube elements at the source, lowering the water potential inside the seive.
  • water enters the xylem by osmosis
  • higher pressure
  • at the sink, sugars leave the phloem to be used causing a higher water potential inside the sieve tubes (sucrose is converted to glucose/ starch to maintain pressure gradient)
  • water leaves via osmosis
  • lower pressure inside seive tubes
64
Q

Development of drug testing- the pre-clinical stage:

A
  • testing isolated cells and tissue cultures
  • animal testing
  • to measure toxicity and efficacy
65
Q

Development of drug testing- phase 1:

A
  • small group of healthy volunteers
  • measures toxicity
66
Q

Development of drug testing- phase 2:

A
  • a small group of patients with the condition
  • dosage, efficacy and toxicity
67
Q

Development of drug testing- phase 3:

A
  • a large group of patients
  • group is divided and one is given the drug and the other the placebo
  • is a double blind trial so neither the doctor nor the patient know who has the drug versus the placebo.
  • measures the efficacy of the drug compared to the placebo effect
68
Q

Why is comtemporary drug testing an improvement from William Withering’s drug protocol?

A

safer:
- pure drug used rather than the extract
- pre-testing on animals and tissure cultures
- regulated by a legislation
more valid:
- placebo used as a comparison
- double blind trial
- controlled variables such as age, gender, lifestyle
More reliable:
- more people are tested
- results are analysed statistically

69
Q

in-situ meaning and examples:

A
  • in an organisms habitat
  • e.g. education programmes or natural parks
70
Q

ex-situ meaning and examples:

A

-outside of an organisms habitat
- e.g. captive breeding programmes, seed banks

71
Q

Captive breeding programme:

A

-endangereed species are carefully bred to increase genetic diversity and population size.
- genetic diversity is maintained via exchange of organisms and gametes, keeping stud books, preventing inbreeding ad use of techniques such as IVF.
- reintroduction programs aim to release animals bred in captivity into their natural habitats as well as restore lost habitats

72
Q

seed banks:

A
  • large number of seeds in order to conserve genetic diversity and prevent plant species from going extinct
  • storing seeds instead of plants means that a large variety of species can be conserved, and is cheaper (takes up less space)
  • seeds are stored in cool, dry conditions
  • they are testes periodically for viability.
73
Q

purpose of education programs:

A
  • aim to educate people about the importance of maintaining biodiversity, captive breeding programmes as well as illegal trade of animal products
74
Q

national parks and sites of scientific interest:

A

conserve habitats and biodiversity

Biology (9 decks)

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