B1 Mendel

Question 1

Who was George Mendel?

Answer 1

An Austrian monk, who noticed how characteristics in plants were passed on from one generation to the next.

Question 2

When was Mendels research published and what did it form the foundations of?

Answer 2

1866

The foundation of modern genetics

Question 3

Outline Mendels research.

Answer 3

1. Mendel crossed a tall pea plant with a dwarf pea plant. All the offspring were tall.
2. Mendel then took two of the tall plants from the first set of offspring and crossed them. This time 75% were tall and 25% were dwarf.
3. Mendel realised that height characteristics in pea were determined by separate inherited factors, passed on from each parent.

Question 4

Draw a genetic diagram to show Mendels findings (2)

T shows factor for tall and is dominant
t is the factor for dwarf

Answer 4

First cross. Second cross
(Parent). TT. tt. Tt. Tt

           T.      T.     t.      t.                                T.    t.         T.      t

(Offspring)
Tt. Tt. Tt. Tt. TT. Tt. Tt. tt

Question 5

What are most characteristics determined by?

Answer 5

The interactions of multiple genes in different parts of the genome.

Question 6

What is genome sequencing?

Answer 6

When scientist work out the order of nucleotides in an organisms genome.

Question 7

What do scientists use genome sequencing to identify?

Answer 7

Which parts of the genome control different characteristics.

Question 8

How is height influenced by DNA sequences?

Answer 8

DNA sequences in over 400 locations within our genome influence height.

Genetic variants in these locations interact with each other to determine how tall we will be.

Question 9

Name a range of purposes scientists can use the information from working out which genetic variants influence different characteristics (2)

Answer 9

To test whether people are susceptible to diseases that are influenced by genetic variants

To modify organisms so they contain a specific gene.

Question 10

Explain how Mendel contributed to modern day understanding of genetic inheritance (3 marks)

Answer 10

Mendel crossed dwarf pea plants with tall pea plants (1 mark)
And discovered that the height of the offspring was influenced by the height of the parents.(1 mark)
This lead to the understanding that there were inherited factors that could control characteristics (1 mark)