Mendel and Inheritance

Question 1

What can variation be caused by?

Answer 1

Variation can be caused by:
* environmental factors
* genetic factors
* a combination of the two.

Question 2

Traits which are caused by genetic
factors can be inherited by …

Answer 2

…offspring

Question 3

The “characteristic” that we see is called the …

Answer 3

…Phenotype

Question 4

The phenotype of eyes may be…

Answer 4

…blue, green, brown

Question 5

Some phenotypes are not…

Answer 5

…observed visually

Question 6

Some phenotypes are not observed visually. They can include
properties such as…

Answer 6

…activity of enzymes. e.g. some people may have a highly active form and some may have a form with low activity.

Question 7

The phenotype is dependent on…

Answer 7

…genes which code for particular
proteins.

Question 8

Most phenotypes are affected by…

Answer 8

…multiple genes but some are controlled by single genes.

Question 9

Each individual has ___ copies of every gene.

Answer 9

Each individual has two copies of every gene.

Question 10

Each individual has two copies of every gene. These may be the
same…

Answer 10

form or different forms.

Question 11

slide 5

Question 12

slide 6

Question 13

The alleles have a particulate nature. WHat does this mean?

Answer 13

they do not mix and blend together in
the progeny but remain separate

Question 14

He explained that the reason that the white colour disappeared during the F1
generation was that the allele for purple was…

Answer 14

…‘dominant’ and the allele for white
was ‘recessive’

Question 15

In genetics we allocate an upper case letter to the…

Answer 15

…dominant trait.

Question 16

Since the dominant trait is purple, we call the gene responsible for it …

Answer 16

…‘P’

Question 17

The recessive trait is given the same letter but in…

Answer 17

…lower case

Question 18

The gene for the recessive trait, white is called…

Answer 18

…‘p’

Question 19

For the true breeding parent plants, they will have two copies of the …

Answer 19

… same
allele.

Question 20

Organisms which have two identical alleles, such as these, are said to be…

Answer 20

…homozygous plants (or homozygotes )

Question 21

Organisms which have two different alleles are said to be …

Answer 21

…heterozygous plants or heterozygotes

Question 22

Organisms which use sexual reproduction produce…

Answer 22

… gametes which come together
to make the offspring, (sperm and eggs in mammals, pollen and egg cells in
plants).

Question 23

Gametes are produced by…

Answer 23

… meiosis (two cell divisions, four daughter cells)

Question 24

Gametes are produced by meiosis (two cell divisions, four daughter cells). So each gamete only contains…

Answer 24

…one allele of each gene.

Question 25

The cells of the pea plant are...

Answer 25

...diploid

Question 26

The cells of the pea plant are diploid, which means they have...

Answer 26

...two alternative variations of a trait, (these may be the same or may be different)

Question 27

Each organism inherits...

Answer 27

... one variation (allele) of the trait from each parent.

Question 28

If the alleles differ, then the...

Answer 28

...dominant one determines the characteristic.

Question 29

The Law of Segregation states that...

Answer 29

... the two alleles for a heritable character segregate during gamete formation.

Question 30

The Law of Segregation states that the two alleles for a heritable character segregate during gamete formation. Therefore,...

Answer 30

...gametes of the F1 plants (heterozygotes) each have a 50% chance of carrying either allele

Question 31

In monohybrid crosses Mendel showed that tall was...

Answer 31

...dominant to dwarf. We know purple is dominant to white

Question 32

Allele pairs segregate...

Answer 32

...independently during gamete formation

Question 33

WHat is Mendel’s Principle of Independent Assortment?

Answer 33

Allele pairs segregate independently during gamete formation

Question 34

We can explain independent assortment on the basis that ...

Answer 34

...chromosomes segregate in meiosis

Question 35

if the alleles T and t are on one pair of homologous chromosomes and the alleles P and p are on another pair or homologous chromosomes then we can see that...

Answer 35

... they can segregate during meiosis when gamete cells are produced

Question 36

Multicellular organisms have...

Answer 36

...many thousands of genes

Question 37

Multicellular organisms have many thousands of genes. Therefore, ...

Answer 37

...there is a high chance that T/t and P/p could have been on the same chromosome.

Question 38

Genes situated in close proximity on the same chromosome are said to be...

Answer 38

...linked

Question 39

In biology we use the probability of 0.05. This means that...

Answer 39

...there is a 5% likelihood that the results could have occurred by chance, so a 95% likelihood that our hypothesis is correct.

Question 40

Remember that during prophase I of meiosis, homologous chromosomes line up adjacent to each other at the equator of the cell and ...

Answer 40

...exchange genetic material

Question 41

Remember that during prophase I of meiosis, homologous chromosomes line up adjacent to each other at the equator of the cell and exchange genetic material. These events are called ...

Answer 41

...crossovers or chiasmata

Question 42

Slide 38 - 45.