Brainscape's Knowledge GenomeTM

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


See full index

A Level Biology > Biology Unit 2 > Flashcards

Biology Unit 2 Flashcards

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

What is variation?

A

Difference in organisms

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

Intraspecific

A

difference between organisms of the same species

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

interspecific

A

difference between organisms of different species

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

Discontinuous variation

A

characteristics fall into certain groups with no overlap. determined by genetics

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

Continuous variation

A

characteristics show a range. determined by genetic and environmental

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

Standard deviation

A

spread of data around the mean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

why is standard deviation better than range

A

range is affected by outliers and its only the largest mine the smallest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

if SD of two different means overlap what does it imply

A

its due to chance and the difference between them is not significant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

if SD of two different means don’t overlap what does it imply

A

its not due to chance and the difference is significant

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

building block of dna

A

nucleotide

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

dna structure

A

2 polynucleotides joined by hydrogen bonds between complementary bases - coils into helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

benefits of dna as a double helix

A

more stable, beneficial in semi conservative replication, more compact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is a gene

A

a section of DNA that contains the coded info for making polypeptides and functional RNA. made out of introns an exons.

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

how does a gene/exon code for a protein

A

made out of sequence of bases
each 3 bases code for one amino acid
therefore sequence of bases determines of triple codes which determine the amino acid sequence = primary structure, secondary into tertiary

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

degenerate

A

each amino acid has more than one triplet code

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

non overlapping

A

each base is read only once

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

universal

A

in all organisms the same triplet codes for the same amino acid

18
Q

stop codes

A

occurs at end of sequence

19
Q

how does mutations lead to non functional enzyme

A 
1. changes in sequence of bases, 
triplet codes, 
amino acids, 
primary and tertiary structure,
active site
  1. substrate no longer complementary
  2. no longer form enzyme- substrate complex
20
Q

what is a chromosome

A

formed during interphase, made of 2 identical chromatids joined by a centromere

21
Q

what is a homologous pair of chromosomes

A

a pair of chromosomes, 1 from mother (maternal) 1 from father (paternal), carries the same genes cos of loci but different alleles - 23 pairs

22
Q

mitosis cell produces

A

2 genetically identical daughter cels, diploid (full set of data)

23
Q

meiosis cell produces

A

4 genetically different daughter cells, haploid (half the data)

24
Q

how does meiosis produce variation

A

crossing over

independent segregation

25
Q

what is crossing over

A

occurs in prophase 1 and meiosis 1, homologous pairs of chromosomes wrap around each other and swap sections of chromatids - produces new combination of alleles.

26
Q

what is independent segregation

A

homologous pairs of chromosomes separate in meiosis 1 and its completely random.

and the chromatids then separate In meiosis 2.

the four daughter cells produced have different combinations of maternal and paternal.

shuffling leads to GV in any potential offspring.

27
Q

difference between metaphase 1 and 2

A

in 1 = homologous pairs line up in centre of cell - 23 pairs

in 2 = single chromosomes line up in middle of cell - 23 chromosomes

28
Q

DNA mass in meiosis

A

quarters

29
Q

chromosome number in meiosis

A

halves

30
Q

genetic diversity

A

the number/ variety of different alleles of genes within a population of/or species

31
Q

benefit of high genetic diversity

A

species able to adapt with changes in the environment

32
Q

what is genetic bottleneck

A

large reduction in population size due to a natural disaster, low number of individuals = low variety of alleles so low genetic diversity

33
Q

adaptations of gills in fish

A

many gill filaments and gill lamella - large surface area

thin wall

permeable

ventilation brings in pure water - high oxygen conc

circulation brings in deoxygenated blood

countercurrent flow maintains conc gradient as flow in opposite directions

34
Q

what is a xerophyte

A

a plant adapted to reduce water loss - survive in dry conditions

35
Q

what is classification

A

placing organisms into groups

36
Q

what is hierarchical classification

A

large groups divided into smaller groups with no overlap

37
Q

species

A

a group of individuals with similar characteristics that can interbreed to produce fertile offspring

38
Q

phylogenetic classification

A

based on evolutionary relationships - how closely related different species are and how recent a common ancestor they have is

39
Q

benefits of courtship behaviour

A
  • identify same species
  • identify opposite gender
  • identify when individuals is ready for mating
  • form a pair bond
40
Q

5 ways an antibiotic can destroy a bacteria

A
  1. prevent cell wall from forming, water enters by osmosis
  2. increase membrane permeability
  3. inhibit DNA replication
  4. inhibit protein synthesis
  5. inhibit respiration
41
Q

how a population of a antibiotic may become resistant to an antibiotic?

A
  • variation in the population
  • some of the bacteria are resistant to the antibiotic - have an antibiotic resistant gene
  • if antibiotic is used, the ones with resistant genes survive and others will die out (selection)
  • the resistant ones will survive and pass on their resistant genes by vertical gene transmission and horizontal gene transmission
  • if this occurs for many generations, then most of the bacteria will be resistant to the antibiotic (adaptation).
42
Q

what is species diversity

A

number of diff species and number of individuals for each species

A Level Biology (9 decks)

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