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Biology > 5.4 > Flashcards

5.4 Flashcards

1
Q

what is the significance of crossing over?

A

creates new allele combinations which add diversity to the gene pool of the population
o The four gametes formed in meiosis will not be identical but rather can have different alleles for each gene.
This therefore increases genetic variation in a population and can introduce new phenotypes that potentially* could be expressed.

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1
Q

what is the significance of fertilisation in predicting variations in offspring

A

further increases the shuffling of genetic material and increases the possibility of variation arising
For this reason siblings always differ from each other either slightly or significantly.

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2
Q

what is the significance of independent assortment and random segregation inregard to potential variations

A

two independent assortment and random segregation introduce (genetic) variation into the alleles that each gamete inherit after Cytokinesis II in Telophase

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3
Q

differentiate between sister chromatids and non sister chromatid?

A

same chromosome or not

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4
Q
  • If the organism has two dominant allele for a particular gene, the __________ allele will be expressed.
A

dominant

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5
Q
  • If the organism has two alleles for a particular gene, one dominant and the other is recessive, the _________ allele will be expressed.
A

dominant

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6
Q
  • If the organism has two recessive alleles for a particular gene, the ? allele will be expressed.
A

recessive

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7
Q

what are autosomes?

A

An autosome is a chromosome in an organism that is not a sex chromosome.

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8
Q

what is the mendel method

A

Mendel crossed a pure breeding tall plant (BB) with a pure breeding short plant. He created two laws of biology based on such information which still applies today.

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9
Q

what does the first law of dominance and segregation state

A

The characteristics of an organism are determined by factors that occur in pairs. Only one member of a pair of factors can be represented in any gamete (segregation). Offspring inherit one factor from each parent. This shows 3:1 overpower.

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10
Q

what is the second law of sorting

A

Mendel’s second law relates to how variation arises in meiosis

In this law, he established further ratios showing that when individuals with two or more pairs of unrelated, contrasting characteristics are crossed (for example, tall plants with yellow pods × short plants with green pods), the different pairs of factors (tall/short and yellow/green) separate out independently of each other

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11
Q

what is autosomal inheritance?

A
  • The process of transferring genes (DNA) present in the parents’ autosomes to offspring is called autosomal inheritance.
  • If it is a 50/50 ratio between men and women the disorder is autosomal
  • Autosomal dominant inheritance : The dominant alleles take over the recessive
  • Autosomal recessive inheritance : the recessive alleles manage to be dominant
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12
Q

what is co-dominance?

A

When two different alleles for the same gene are present and both are expressed as separate, unblended phenotypes.
* equally dominant and both expressed

-cow have both brown and white colour pathes on its skin

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13
Q

what is incomplete dominance

A

When one allele of a gene is not completely dominant upon another allele of the same gene, then the phenomenon is known as incomplete dominance.

  • snapdragon flower
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14
Q

what is sex linked inheritance

A

Sex chromosomes carry genes that determine the sexual characteristics of a person and therefore influence whether they are male or female

Females have a pair of sex chromosomes XX, males being XY, with y being shorter and therefore not carrying a sex-linked gene

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15
Q

what are multiple alleles

A

In cases of multiple alleles, there are more than two alleles that exist for a particular gene.
However, only TWO ALLELES may be present in any individual at a single locus

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16
Q

what is the use of a pedigree

A

A pedigree chart can be used to record phenotypes and work out the genotypes of a family, in order to study hereditary patterns, mutations that result in diseases and predict for future offspring

  • Determine inheritance patterns
  • Assign genotypes to individuals where possible
  • Make predictions about the risk/probability of an individual inheriting a trait
17
Q

in a pedigree a cirlce and square refer too»

A

differing genders : circle being women square being men

18
Q

what is a diamond used for in a pedigree

A

unknown gender : unborn baby

19
Q

what does a shaded circle indicate in a pedigree

A

has the affected trait

20
Q

what does a half shade indicate in a pedigree

A

a carrier of the disease/trait

21
Q

what r the 4 characteristics present in an autosomal domanince pedigree

A
  • equal chance of appearing in both genders
  • trait cannot skip a generation row
  • affected can either have one or two parents affected
  • heterozygous parents express the dominant trait can have an unaffected offspring
22
Q

what r the 4 characteristics present in an autosomal recessive inheritance

A
  • the trait has equal chance to appear
  • trait can usually skip a row
    • If both parents expresses the recessive trait, all of the offspring must express the recessive trait.
    • Affected offspring expressing the recessive trait could have two unaffected heterozygous parents
23
Q

what are the 4 characteristics presentin a sex linked dominance pedigree

A
  • affected father will pass his x linked trait to his daughter but not son
  • mother- father/mom (either)- if father the daughter will get it
  • trait CANNOT be skipped in a row
  • expressed more in females then males
24
Q

what r 4 characteristics that are present in sex linked recessive inheritance pedigrees

A

-affected father will give trait to his daughter but no son
-if mother is affected, all sons are affected
-trait can skip a row
-if mother is a carrier n father isnt affected, the son will have a 50% chance to be affected n daughter will not be affected

-if mother carrier and father affected all kids have an equal chance of getting it

25
Q

what is population genetics?

A

The study of how the gene pool of a population changes over time, leading to a species evolving

26
Q

what is the purpose of population genetics?

A
  • combines mendelian genetics and Darwinian evolution to explain how changes in allele frequencies arise and how they can lead to microevolution and macroevolution
  • scientists measure the degree of genetic variation in a population overtime to make predictions about how populations adapt to their environments and which populations are most likely to evolve or die out.
27
Q

how to get the allele frequency

A

number of copies of alleles (g) in a population/ total number of copies of gene (G+ g) in population

28
Q

how to get the genotypic frequency?

A

number of particular genotype./ total number of genotype in a population

29
Q

how to find the phenotypic frequency

A

number of particular phenotype in a population/total number of phenotypes in a population

30
Q

why collecting data is important?

A

gathering quantitative data and applying abstract mathematical model predict how external factors influence frequencies such as bottleneck effect or a founder effect

31
Q

why is data limited in regard to phenotypes and sampling?

A
  • Phenotypes do not always indicate genotype
  • Sampling may not include a sufficient sample size
  • Sampling may be insufficient to reflect the whole population gene frequency
32
Q

what is the hardy-weinberg principle

A
  • mathematical model that calculates allele frequency of traits with dominant and recessive alleles
  • calculate allele frequency of a gene in the population to show changes in frequency overtime

p^2+2pq+q^2=1

33
Q

what is genetic drift?

A
  • Random changes in allele frequency from one generation to another
  • In a large population = has a small effect on population/little impact on genetic diversity and evolution
  • Small population = genetic drift has a large effect on genetic diversity and evolution
34
Q

what are single nucleotide polymorphisms?

A

Single nucleotide polymorphism is where one nucleotide in the genome of an individual is different to the rest of the population’s nucleotide at the same location in the DNA or gene. This is because, due to SNP, a new nucleotide randomly replaces or substitutes an existing nucleotide in the organism’s DNA sequence.

35
Q

For a change in DNA sequence to be considered a SNP, the same SNP must be experienced by organisms in at least……

A

1% or more of the species’ population. if not the change is deemed a mutation.

36
Q

99% of all SNPs events occur…

A

outside the coding region of the dna responsible for specifying for a protein (non-coding_

outside the coding region of DNA will NOT have a direct effect on the organism’s ability to function normally as the majority of SNPs mainly occur in the non-coding areas of the DNA as they dont specify for a protein.

37
Q

what are the two groups in coding snps

A

non-synonymous and synonymous

38
Q

differentiate between non-synonymous and synonymous snps

A

in synonymous, the protein structure and function will NOT be affected

in non-synonymous, the change in codon sequence will alter the chain in amino acids. there r two types mis sense which will specify a differeny amino acid and non sense where the stop codon will occur at the wrong time.

39
Q

what is the importance of collecting data using technology in SNPs

A

SNPs can have an effect on altering the physical, physiological and even behavioural traits (e.g. personality) or characteristics such as of an organism.

Genome-wide association studies (GWAS) employs computer technologies to obtains a detailed report on the genome of individuals. Researchers scan the sections of DNA that have the greatest variance amongst species the population and documenting the SNPs of the scanned individuals.

By obtaining genome reports of individuals with and without a trait (or with and without disease) in the population, scientists can attempt to determine the genes that are responsible for certain traits or diseases. This is done by comparing the frequency of SNPs that appear between an affected individual and an unaffected individual.

the higher the frequency of SNPs, the more likely those SNPs are related to the trait or disease the affected individual has developed.

40
Q

what are limitations in regard to collecting data on SNP’s

A
  • Technology can never prove that it is 100% SNP’s effect
    o scientists would still require taking into account of the environment factors that may contribute to an individual developing the trait (or disease) of concern.
  • Diseases can also be monogenic or multigenic. Monogenic are caused by one ‘faulty’ gene whereas multigenic is caused by multiple ‘faulty’ gene.
41
Q

the greater the genetic diversity a population has…..

A

the more capable it is able to adapt to changing selective pressures in the environment which the species residues in.

Biology (9 decks)

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