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Biology > Inheritance, variation and evolution > Flashcards

Inheritance, variation and evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Asexual reproduction

A

Reproduction in which a single parent produces offspring that are genetically identical to the parent

No mixing of gametes
Mitosis

e.g. strawberries, malaria

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2
Q

sexual reproduction

A

A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents

Uses gametes (sperm, egg or pollen)
Meiosis

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3
Q

Stages of mitosis

A

Interphase—DNA is copied, cell doubles in size
prophase—Nuclear membrane disappears (beginning of mitosis)
metaphase—chromosomes line up in the centre of the cell
anaphase—each chromosome spits into 2 chromatids, which split and are pulled to the edge of the cell
telophase—nuclear membrane reforms (end of mitosis)
cytokinesis—cytoplasm divides, leaving 2 full identical cells

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4
Q

Stages of meiosis

A

Interphase, Prophase I, Metaphase I, Anaphase I, teleophase I, cytokinesis, Prophase II, Metaphase II, Anaphase II, Telophase II, cytokinesis

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5
Q

Haploid cells contain

A

23 chromosomes
Sex cells need half, so when 2 haploid cells combine, they produce a diploid number

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6
Q

Diploid cells contain

A

23 pairs of chromosomes (46 chromosomes)

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7
Q

Advantages of sexual reproduction

A
  • Creates a lot of genetic variation among offspring, so evolution happens faster (a bit of a double-edged sword)
  • Allows selective breeding
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8
Q

Advantages of asexual reproduction

A
  • 1 parent needed
  • Faster
  • More energy efficient (don’t have to look for a mate)
  • Identical offspring (a bit of a double-edged sword)
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9
Q

Genome is

A

all of an organism’s genetic material

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10
Q

Gene

A

A segment of DNA on a chromosome that codes for a specific trait

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11
Q

Phenotype

A

the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

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12
Q

Allele

A

An alternative form of a gene.

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13
Q

What is in one nucleotide (1 monomer of the DNA polymer)
What is the structure of DNA

A
  • a sugar (not glucose)
  • a phosphate
  • One of 4 bases, Adenine, Thymine, Guanine, Cytosine (ACGT)
  • 2 nucleotides are linked together to form the double helix
  • C links to G and A to T
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14
Q

What is a codon

A

a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

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15
Q

How does protein synthesis occur?

A

Transcription—DNA code is copied to make mRNA Translation—tRNA brings amino acids to the ribosomes to make an amino acid sequence
The amino acid sequence folds into a protein

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16
Q

What are mutation

A

Changes to the DNA may result in changes to the protein produced which may cause that protein to not function or not function as well which can affect the organism, especially if lots of cells then copy this change through mitosis

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17
Q

Do all parts of DNA code for proteins?

A

No, Non-coding parts of DNA can switch genes on and off, so variations in these areas of DNA may affect how genes are expressed

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18
Q

How should we care about Gregor Mendel

A

He did experiments with pea plants
He discovered a genetic unit (now called a gene) that was passed down from parents to children
He disproved the idea that sexual reproduction blended characteristics (e.g. breeding a red and white flower makes a pink one)

Work was not recognised because he was a monk not a scientist so did not publish his work

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19
Q

Genotype

A

The combination of alleles present in a gene (e.g. having the dominant brown-eyed gene from your mum and recessive blue-eyed gene from your dad)

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20
Q

Homozygous

A

An organism that has two identical alleles for a gene e.g. BB

21
Q

Heterozygous

A

An organism that has two different alleles for a gene e.g. Bb

22
Q

Polydactyly

A

A genetic disorder causing a person to have more than the normal number of fingers or toes

Caused by a dominant allele

23
Q

Cystic fibrosis

A

A genetic disorder that is present at birth and affects both the respiratory and digestive systems.
A disorder of the cell membranes

Caused by a recessive allele

24
Q

How is sex determined?

A

A man will have a Y and an X chromosome and a woman has two X’s

One X comes from the mother and either an X or a Y from the father

25
Q

Variation is

A

Differences in the characteristics of individuals in a species

Can be caused by either environmental or genetic differences

26
Q

Evolution is

A

The gradual change in the inherited characteristics of a population. This can lead to the creation of new species.

27
Q

How did Darwin come to his theory

A

He noticed that:
- organisms produce a large number of offspring
- populations stay roughly the same size
- variation exists
- characteristics can be inherited

Hence:
- there is a struggle for existence
- not everyone is a winner, so not all that are born can survive
- the fittest ones do survive and so reproduce
- so the next generation are made up of the genes of the fittest organisms
- this process constantly repeats

28
Q

Why should we care about Jean-Baptiste Lamarck

A

His theory of evolution has based on nurture not nature
e.g. a giraffe got taller by reaching up passed on hoe tall it got over its life to its offspring who could then reach a bit higher

29
Q

What evidence is there for evolution?

A

Fossils provide an insight on how organisms have evolved over time (but many early organisms were soft bodied and so did not leave fossils)
Species such as horses have good fossil records, for example, so we can see them change over time

Antibiotic resistant bacteria’s development

30
Q

Discontinuous variation is

A

Variation where there are distinct categories and nothing in between (e.g. the human ABO blood group)

31
Q

Continuous variation is

A

Variation measured on a continuum rather than in discrete units or categories (eg height in human beings).

32
Q

What makes a species a species

A

A species is defined as a group of organisms capable of producing fertile offspring.

33
Q

Speciation is

A

the formation of new and distinct species in the course of evolution.

34
Q

Allotropic speciation

A

Formation of a new species in populations that are geographical isolated from one another (includes physical barrier)

35
Q

Sympatric speciation

A

The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population and the parent population. No geographic barrier is present. (e.g. a new mating dance in TFR birds),.

36
Q

How does selective breeding work?

A

From your existing stock, select those with the desired characteristic(s) you want and breed them together.
Then select the best offspring and breed them together.
Continue this over several generations and the characteristic becomes stronger and stronger at the desired characteristic(s).

37
Q

Advantages and disadvantages of selective breeding

A

Characteristics can be selected such as:
- disease resistance (more in crops than animals)
- producing more food
- domestic dogs
- larger flowers

But it can lead to inbreeding due to a lack of genetic diversity

38
Q

How to genetic engineer

A
  • Cut the required section of DNA using restriction enzymes
  • Spice the DNA into a bacteria or virus plasmid using ligase enzymes, this is now a recombinant plasmid
  • Insert the plasmid inside a harmless bacteria or virus, now called a vector
  • Antibiotic resistance should also be included in the DNA section
  • Expose the vectors to antibiotics to remove none vectors from the solution
  • Allow the vectors to multiply
  • Inject the vectors into the transgenic organism

this process is done while the organism is an embryo, then the entire organism will gain the trait,
not just the small area exposed to the vector

39
Q

Concerns of gm

A
  • long term effects on natural populations
  • long term effects on human health
  • ethics and religious concerns
  • creating monopolies on types of crop
40
Q

Transgenic

A

A genetically modified organism

41
Q

How to clone a plant

A

Take cuttings then plant the stem
Growth hormones can be used to encourage roots

42
Q

How to clone an animal

A

Remove the nucleus from an unfertilised egg cell
Insert the nucleus from the organism you wish to clone into the unfertilised egg cell
Shock the egg cell to stimulate cell division
Allow it to develop into an embryo
Insert the embryo into the surrogate female to continue development

43
Q

Surrogate

A

(n.) one acting in place of another (The surrogate carried the child to term for its biological parents.)

44
Q

Why do we care about Carl Linnaeus

A

Kingdom → Phylum → Class → Order → Family → Genus → Species
(Keep plucking chickens or fear getting sacked)

and the binominal naming system (genus + species)

45
Q

Why do we care about Carl Woese

A

The addition of the Domain to Carl Linaeus’ system
The domains are:
- archaea
- bacteria
- eukaryota

46
Q

Artificial classification

A

Grouping by visible characteristics (e.g. fish all swim in the sea)

47
Q

Natural classification

A

Groups together organisms descended from common ancestors (e.g. fish do not exist)

48
Q

Why do we care about Alfred Russel Wallace

A

Idea of allotropic speciation

Populations separated both have variation and both are acted on by evolution
Eventually they will not be able to breed as they will be too different, thus speciation has occurred

Biology (6 decks)

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