Biology

Question 1

What are the building blocks of DNA?

Answer 1

Nucleotides

Question 2

What are the components of a nucleotide?

Answer 2

Phosphate group, Pentose sugar, Nitrogenous bases

Question 3

What Components form the DNA backbone?

Answer 3

Sugar and phosphate

Question 4

What components form the rungs?

Answer 4

The nitrogenous bases

Question 5

What are the four types of nitrogenous bases?

Answer 5

Adenine, Thymine, Cytosine and Guanine

Question 6

What is complementary base pairing?

Answer 6

bases bonding with one other specific base

Question 7

Why does DNA have a double helix?

Answer 7

To make it more compact

Question 8

Where is the DNA located in the cell?

Answer 8

The nucleus holds DNA (genetic information)

Question 9

How is DNA organised in the nucleus?

Answer 9

It’s organised into units called genes, genes are found on chromosomes.

Question 10

What is a gene?

Answer 10

A segment of DNA that codes for a particular protein (e.g eye colour)

Question 11

How many pairs of chromosomes do humans have?

Answer 11

23 pairs or 46 total

Question 12

What does diploid mean?

Answer 12

A paired set of chromosomes in somatic cells

Question 13

What is a somatic cell?

Answer 13

Cells of the body except sex cells

Question 14

What are gametes?

Answer 14

Reproduction or sex cells (sperm and egg)

Question 15

What does haploid mean?

Answer 15

The possession of one copy of each chromosome in a cell.

Question 16

What sex chromosomes do females have?

Answer 16

XX

Question 17

What sex chromosomes do males have?

Answer 17

XY

Question 18

What is an autosome?

Answer 18

Any chromosome not included in sex determination

Question 19

What is a sex chromosome?

Answer 19

The chromosomes that determine an individuals sex

Question 20

What is a karyotype?

Answer 20

A karyotype is the visualisation of an individual’s collection of chromosomes

Question 21

What is the purpose of a karyotype?

Answer 21

To look at abnormal numbers or structures of chromosomes

Question 22

What is a homologous chromosome?

Answer 22

The same size, shape and carry the same genes

Question 23

Where do you get the matching pairs?

Answer 23

One of the pair from your Mother and one of the pair from your Father

Question 24

What is an allele?

Answer 24

A different version/form of a gene, e.g brown eyes, blue eyes

Question 25

What is the difference between a gene and an allele?

Answer 25

A gene specifies a trait, allele specifies the form a gene takes

Question 26

What are dominant alleles?

Answer 26

Alleles that will always be expressed when they’re present

Question 27

What are recessive alleles?

Answer 27

Alleles that are only expressed when there are two recessive alleles

Question 28

What is a genotype?

Answer 28

The alleles that a person has e.g Bb

Question 29

What is a phenotype?

Answer 29

The trait that is seen e.g brown eyes

Question 30

What does homozygous mean?

Answer 30

the same alleles e.g BB or bb

Question 31

What does heterozygous mean?

Answer 31

Different alleles e.g Bb

Question 32

What is a genetic cross?

Answer 32

Genetic crosses are used to measure the probability for a specific cross

Question 33

What’s a punnet square?

Answer 33

A tool to do a genetic cross

Question 34

How to complete a genetic cross?

Answer 34

1. Designate characters to represent alleles (e.g, A = dark red cross; a = light red
2. Write the genotype and phenotype of the parents (e.g, dark red cross Aa x Aa)
3. Use a grid to work out gamete combinations
4. Write the genotype and phenotype ratios of offspring

Question 35

What is a pedigree chart?

Answer 35

It is a chart of the genetic history of a family over several generations

Question 36

What symbols are used?

Answer 36

Female: circle, Male: square

Question 37

How do you determine if the pedigree chart shows an autosomal or x-linked disease/trait?