Flashcards in 3.7.1 Inheritance Deck (63)

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1

## What is a genotype?

### The genetic make up on an organism. It describes ALL the alleles that an organism has.

2

## What is an allele?

### A different version of the same gene

3

## What is a gene?

### Short section of DNA made up of nucleotide bases, which codes for a specific order of amino acids which makes a protein.

4

## What is a phenotype?

### Observable characteristics due to environment and genetic makeup

5

## What is a homologous pair?

### A pair of chromosomes - maternal and paternal. Also known as a bivalent

6

## What is a recessive allele?

### An allele whereby you need 2 copies of it (homozygous) to express that characteristic. Its not expressed if the dominant allele is present.

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## What is a dominant allele?

### You only need ONE copy of this allele to express this characterisitic

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## Homozygous dominant means?

### Two dominant alleles present (in the genotype)

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## Homozygous recessive means?

### Two recessive alleles present (in the genotype)

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## Heterozygous means?

### One recessive and one dominant allele present (in the genotype)

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## A codominant allele is?

### Where both alleles contribute/expressed in the phenotype

12

## What are multiple alleles?

### Where you have more than two alleles for a particular gene

13

## In a diploid organism (human) how many chromosome pairs are there?

### 23

14

## In meiosis what happens to the diploid number?

### It becomes haploid - halves

15

## Characteristics are determined by your allele combinations, how many alleles for each characteristics end up in the gamete?

### 1

16

## Pure breeding plants are said to be

### Homozygous

17

## If there are 30 boys and 15 girls what is the ratio?

### 2:1

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## Why are actual ratios not exactly the same as theoretical ratios in genetics?

### Because fertilisation of gametes occurs by chance - each time a gamete is fertilised, it is an independent event of what has gone before it.

19

## How can you try and get theoretical ratios to match observed/actual ratios?

### Increase sample size so its more representative

20

## If you were to perform a statistical test on Mendelian genetics and you where looking at observed and expected ratios - what test would you do and why?

### Chi Squared - because you are comparing observed and expected values and determining if there is a statistical difference

21

## Suppose you obtained a chi squared value of 5 and the critical value was 5.99 (2dof) - what can you conclude?

### Because the chi squared value is SMALLER than the critical value - you accept the null hypothesis and there is greater than a 5% probability that the difference in the results are due to chance. There is no significant difference.

22

## Suppose you obtained a chi squared value of 8 and the critical value was 5.99 (2dof) - what can you conclude?

### Because the chi squared value is LARGER than the critical value - you reject the null hypothesis and there is less than a 5% probability that the difference in the results are due to chance. There is a significant difference.

23

## What is the difference between monohybrid inheritance and dihybrid inheritance?

### Monohybrid is the inheritance of a SINGLE gene, dihybrid is the inheritance of TWO genes (that are located on different chromosomes)

24

## Give an examples of a characteristic that involves multiple alleles

### Blood groups - IA, IB and IO

25

## Identify the chromosomes that determine sex

### Sex Chromosomes - X and Y

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## Female sex chromosomes are

### XX

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## Male Sex Chromosomes are

### XY

28

## Which sex determines the sex of the child?

### Males - as females always pass on a X in their gametes.

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## What are the criteria must be met to perform a chi squared test?

### sample size is large (20+), data falls into catergories (green, yellow), compare experimental observations with theoretical ones (expected)

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