B16 - Inheritance

Question 1

What are chromosomes made of, and what do they contain?

Answer 1

Chromosomes are made of DNA, which contains genetic information in the form of genes

Question 2

Gene definition

Answer 2

A (short) length of DNA that codes for a protein

Question 3

Allele definition

Answer 3

An alternative form of a gene

Question 4

How is sex inherited in humans with reference to XX and XY chromosomes?

Answer 4

In humans, females have two X chromosomes (XX), and males have one X and one Y chromosome (XY). The inheritance of sex is determined by the X or Y chromosome contributed by the father

Question 5

What is a haploid nucleus?

Answer 5

A nucleus which contains a single set of chromosomes.

Question 6

What is a diploid nucleus

Answer 6

A nucleus containing two sets of chromosomes

Question 7

What is the chromosome structure in a diploid cell, and how many pairs are there in a human diploid cell?

Answer 7

In a diploid cell there is a pair of each type of chromosome
In a human diploid cell there are 23 pairs

Question 8

Mitosis definition

Answer 8

Nuclear division giving rise to (resulting in) genetically identical cells

Question 9

What is the role of mitosis?

Answer 9

Mitosis is responsible for growth, repair of damaged tissues, replacement of cells, and asexual reproduction

Question 10

When does the exact replication of chromosomes occur in relation to mitosis?

Answer 10

The exact replication of chromosomes occurs before mitosis

Question 11

What happens to the copies of chromosomes during mitosis?

Answer 11

During mitosis, the copies of chromosomes separate, maintaining the chromosome number in each daughter cell

Question 12

What is the role of meiosis?

Answer 12

Meiosis is involved in the production of gametes

Question 13

Meiosis definition

Answer 13

Reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells

Question 14

Define inheritance

Answer 14

transmission of genetic information from generation to generation

Question 15

Where are chromosomes found?

Answer 15

nucleus of a cell

Question 16

What are chromosomes made of

Answer 16

DNA
-contain genetic information in form of genes

Question 17

Define gene

Answer 17

length of the DNA that codes for a protein

Question 18

Define allele

Answer 18

alternative form of a gene

Question 19

What chromosomes do female eggs contain

Answer 19

X, X

Question 20

What chromosomes do male sperms contain

Answer 20

X, Y

Question 21

What combination of chromosomes does a female zygote contain

Answer 21

XX

Question 22

What combination of chromosomes does a male zygote contain

Answer 22

XY

Question 23

What are the chances of the sex for the baby

Answer 23

0.5

Question 24

Describe Haploid Nucleus (2)

Answer 24

Haploid nucleus is a nucleus that contains one set of chromosome
- gametes, sex cells

Question 25

Describe Diploid Nucleus (3)

Answer 25

Diploid nucleus is a nucleus that contains two sets of chromosomes - normal human cells (23 pairs) - has a pair of each type of chromosome

Question 26

What is Mitosis?

Answer 26

nuclear division creating genetically identical daughter cells

Question 27

What are the roles of Mitosis? (4)

Answer 27

1. growth 2. repair of tissues 3. replacement of cells 4. asexual reproduction

Question 28

Stages of Mitosis (5)

Answer 28

1. Chromosomes create identical copies of themselves (DNA replication) 2. similar chromosomes pair up 3. Chromatids are pulled apart 4. chromosomes separate 5. Cells divide (2 daughter cells are made that are genetically identical)

Question 29

What is Meiosis? (4)

Answer 29

the reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells

Question 30

What are the roles of Meiosis? (2)

Answer 30

1. creates haploid cells by reduction division 2. produce genetic variations

Question 31

What are the stages of Meiosis

Answer 31

1. Chromosomes create identical copies of themselves (DNA replication) 2. similar chromosomes pair up 3. sections of DNA are swapped 4. chromosomes are pulled apart --> first division 5. chromosomes are divided again (resulting in 4 daughter cells) --> second division

Question 32

Define genotype

Answer 32

The genetic make-up of an organism and in terms of the allele present

Question 33

Define Phenotype

Answer 33

the observable features of an organism

Question 34

Define Homozygous

Answer 34

having two identical alleles of a particular gene

Question 35

Define Pure-bred

Answer 35

When two homozygous individuals breed together, the offspring is pure bred

Question 36

Define Heterozygous

Answer 36

Having 2 different alleles of a particular gene

Question 37

Define not-pure bred

Answer 37

A heterozygous individual will not be pure-breeding

Question 38

Define dominant allele

Answer 38

an allele that is expressed if it is present in the genotype

Question 39

Define recessive allele

Answer 39

an allele that is only expressed when there is no dominant allele of the gene present in the genotype

Question 40

DD x DD= ?

Answer 40

1- D (dominant)

Question 41

dd x dd= ?

Answer 41

1- d (recessive)

Question 42

Dd x Dd= ?

Answer 42

3:1- D (dominant): d (recessive)

Question 43

DD x dd= ?

Answer 43

1- D (dominant)

Question 44

Dd x dd= ?

Answer 44

1:1 -D (dominant): d (recessive)

Question 45

How is a 'normal' female identified in a pedigree chart?

Answer 45

empty circle

Question 46

How is a 'normal' male identified in a pedigree chart?

Answer 46

empty square

Question 47

How is an 'affected' female identified in a pedigree chart?

Answer 47

filled in circle

Question 48

How is an 'affected' male identified in a pedigree chart?

Answer 48

filled in square