B5.1 - Inheritance Flashcards Preview

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Flashcards in B5.1 - Inheritance Deck (51)
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1

Define a phenotype

The appearance of an organism

2

Define variation

The differences within a species

3

What are the two types of variation, explain

Genetic variation (genetic material inherited from parents)
Environmental variation (variation caused by your environment - ie. sunlight, hair length - if you cut it or not)

4

Are most features caused by a single gene or multiple?

Usually multiple genes

5

What is discontinuous variation?
(how to show graphically)

- variation that can only result in discrete values (one)
- ONLY GENETIC
- ie. blood group, gender, eye colour
- bar chart

6

What is continuous variation?
(how to show graphically)

- variation that can take any value within a range
- genetic + environmental
- ie. length of fur, skin colour, leaf surface area
- histogram (single line)

7

Define a clone

An organism that is genetically identical to its parent

8

What is asexual reproduction?

When a single organism reproduces itself (by mitosis), and produces new daughter cells genetically identical to itself

9

What is different between the offspring in sexual and asexual reproduction and why?

Asexual reproduction has the exact same genetic material as the parent, whereas sexual is not identical to parents as the offspring takes genetic information from both parents

10

Define gametes

Sex cells (ie. sperm cell, egg cell)

11

What happens during fertilisation?

Two gamete fuse together

12

Advantages/ disadvantages of asexual reproduction?

Adv - if parent well adapted, offspring has identical characteristics
- one parent needed (reproduction faster = more offspring)

Dis - adapted to one habitat (may all die out if abiotic factors change)
- lack of variation, one disease can wipe our all

13

Adv/Dis of sexual reproduction?

Adv - variation leads to adaptations (if environment changes, at least one organism can survive + reproduce)

Dis - reproduction needs two parents (slower = less offspring)

14

What are diploid cells in humans?
(how many chromosomes)

Normal body cells (46 chromosomes)

15

What are haploid cells in humans?
(How many chromosomes)

Sex cells (ova/sperm cells) - 23

16

What is formed when two gamete cells join together?

Diploid cell or ‘zygote’

17

What process causes the zygote to divide many times to produce a new organism?

Mitosis

18

Define genome

All the genetic material within an organism

19

How is meiosis used in the body?

To produce gametes/ sex cells

20

What kind of cells are present at the start of meiosis and what are present at the end?

ONE diploid parent cell at start
FOUR haploid daughter cells at end

21

Where does meiosis occur in females, and males?
(And what is produced)

Females - ovaries (makes ova cells)
Male - testes (sperm cells)

22

Draw out how meiosis works + label diagram

Look at diagram on p155

23

Define alleles

Different forms of a gene

24

What’s the different between dominant and recessive alleles?

Dominant - will always show up
Rr or RR

Recessive - only show up if there are two of them
only rr

25

Define a genotype

The combination of alleles present in an organism

26

What does the genotype of a dominant homozygous individual look like/ a recessive homozygous/ and a heterozygous

GG/ gg/ Gg

27

Give 3 examples of dominant characteristics

Give 3 examples of recessive characteristics

DOM - free ear lobes
- brown eyes
- dark, wavy hair

REC - joined ear lobes
- blue eyes
- straight, blonde hair

28

Who figured out the basic laws of inheritance of characteristics?
(And how)

Mendel (was a Catholic monk)
Carried out experiments on pea plants

29

In the genetic cross between a man who is heterozygous for the Huntington’s allele and a woman who is homozygous recessive for the Huntington’s allele (h).

State the proportion of
(a) homozygotes dominant offspring
(b) heterozygous offspring
(c) homozygotes recessive offspring

(a) 0%
(b) 50%
(c) 50%

30

(A) What does a female’s 23rd pair of chromosomes look like?
(B) what does a male’s 23rd pair of chromosomes look like?

(A) XX
(B) XY