Brainscape's Knowledge GenomeTM

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


See full index

A-Level Biology > 7A - Genetics > Flashcards

7A - Genetics Flashcards

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

What is a gene?

A
  • sequence of bases on a DNA molecule that codes for a protein which results in a characteristic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are alleles?

A
  • different versions of the same gene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a genotype?

A
  • genetic makeup of an organism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a phenotype?

A
  • expression of the genotype and it’s interaction with the environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is meant by a dominant allele?

A
  • an allele whose characteristic appears in the phenotype even when there’s only one copy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is meant by a recessive allele?

A
  • an allele whose characteristic only appears in the phenotype if two copies are present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are co-dominant alleles?

A
  • alleles that are both expressed in the phenotype
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is meant by a locus?

A
  • fixed position of a gene on a chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a homozygote?

A
  • an organism that carries two copies of the same allele
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a heterozygote?

A
  • an organism that carries two different alleles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a carrier?

A
  • a person carrying an allele which is not expressed in the phenotype but that can be passed on to offspring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is meant by a diploid?

A
  • 2 sets of chromosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a gamete?

A
  • sex cells containing only one allele for each gene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of genetic diagrams (Punnett squares)?

A
  • used to predict the genotypes and phenotypes of the offspring produced if two parents are crossed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is monohybrid inheritance?

A
  • inheritance of a characteristic controlled by a single gene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is meant by multiple alleles?

A
  • when there are more than two alleles for the same gene e.g. blood group
17
Q

What is dihybrid inheritance?

A
  • inheritance of two characteristics which are controlled by different genes at the same time
18
Q

What are the 3 reasons for not getting the predicted phenotypic ratio?

A
  • sex linkage
  • autosomal linkage
  • epistasis
19
Q

What is sex linkage?

A
  • when an allele coding for a characteristic is located on a sex chromosome
20
Q

Why are most genes carried on the X chromosome?

A
  • Y chromosome is smaller than the X chromosome and therefore carries fewer genes
21
Q

Why are males more likely to inherit sex-linked recessive traits?

A
  • As males have only one X chromosome, they often only have one allele for sex-linked genes
  • because they have only one copy, they express the characteristic of this allele even if it’s recessive
22
Q

Why are males more likely to inherit colour-blindness or haemophilia?

A
  • faulty alleles for both of these disorders are carried on the X chromosome
  • males only need one copy if the recessive allele they are more likely than females to have this disorder
23
Q

What is autosomal linkage?

A
  • genes present on the same, non-sex chromosome
24
Q

What is the result of autosomal linkage?

A
  • since the genes are linked, they’ll stay together during the independent segregation of meiosis I
  • alleles will be passed onto offspring together unless there is crossing over
25
Q

What is crossing over?

A
  • process in which homologous chromosomes exchange portions of their chromatids during meiosis
26
Q

What is the relationship between genes on a autosome?

A
  • the closer together two genes are on the autosome, the more closely linked they are as crossing over is less likely to split them up
27
Q

What is epistasis?

A
  • a type of gene interaction in which the allele of one gene masks the expression of the alleles of other genes
28
Q

What is Chi-squared test?

A
  • A statistical test used to see if the results of an experiment support a theory
29
Q

What is a null hypothesis?

A
  • that there’s no significant difference between the observed and expected results (negligible difference is due to chance)
30
Q

What is the function of Chi-squared test?

A
  • to compare the goodness of fit of the observed and expected results
  • so the outcome either supports or rejects the null hypothesis
31
Q

What is the formula for Chi-squared test?

A
  • x^2 = sum of (observed-expected)^2 / expected
32
Q

What is a critical value?

A
  • a value that corresponds to a 5% level of probability that the difference between the observed an expected results due to chance
33
Q

What does it mean when calculated value is larger than the critical value?

A
  • there is a significant difference between the observed and expected results
  • null hypothesis can be rejected
34
Q

What is the degrees of freedom?

A
  • no. of categories - 1

A-Level Biology (19 decks)

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