Chaoter 6.1 Flashcards Preview

Biology > Chaoter 6.1 > Flashcards

Flashcards in Chaoter 6.1 Deck (43):
1

Give an example of an visible genetic difference

-Coat colour of llama

2

Give an example where the genetic difference isn't visible

-Owls

3

What is genetic diversity?

-variation or inherited genetic difference in a species

4

Give 2 facts about genetic diversity.

-result of sexual reproduction
-randomly sorts, shuffles DNA

5

What is diploid number?

-Body cell that has two sets of chromosomes

6

What is the human diploid number?

46 (23x2)

7

How does mitosis help diploids?

-Makes sure diploid number always stays the same and genetic information contained in body always remain the same unless mutation

8

Why does genetic diversity within a species is more advantage than a species with no genetic diversity?

Organisms will have combinations of genes from parents, allow it to cope with changes in environment

9

What is haploid number?

One set of 23 chromosomes from female parent and one set of 23 chromosomes from their male parent

10

What are haploid chromosomes carried in

Gametes

11

What are gametes?

Specialized cells necessary for reproduction

12

What are male gametes called

Sperm

13

What are female gametes called

Egg cells

14

What is fertilization

The process which an egg cell is penetrated by a species cell and haploid genetic information from sperm and egg cells combine

15

What is a zygote

New diploid cell formed by fertilization,
Half chromosomes from female half from male

16

What is embryo

The stage of a multicellular organism following fertilization

17

What is the difference between a zygote and embryo

Zygotes undergoes mitosis
Cell division developes into embryo

18

What is meiosis

Process that produces sperms and eggs

19

Name the steps of meiosis


Meiosis 1:
-Prophase 1
-Metaphase 1
- Anaphase 1
- Telophase 1
-interkinesis

Meiosis 2:
-Prophase 2
-Metaphase 2
-Anaphase 2
-Telophase 2
-Cytokinesis

20

Why is meiosis important?

Without meiosis, joining of sperm and egg cell during fertilization would produce offspring with two times original number of chromosomes

21

What are the homologous chromosomes

A pair of matching chromosomes

22

Describe the steps of meiosis 1

Prophase 1: homologous chromosomes pair up, crossing over

Metaphase1: homologous chromosomes pair up at equator

Anaphase1: homologous chromosomes separated by SPINDLE
FIBRES, independent assortment

Telophase1: one chromosome from
homologous pair at each pole of cell

Interkinesis: stage between cell division, cell grows and makes protein NO REPLICATION OF DNA

23

Describe the steps of meiosis 2

Prophase 2: one chromosome of homologous pair in each cell

Metaphase 2: chromosomes from single line across middle

Anaphase 2: sister chromatids move to opposites poles of cells

Telophase 2: spindle fibres begin to disappear, nuclear membrane forms around each set chromosomes

Cytokinesis: two daughter cells seperated

24

What is the result of meiosis 1

-2 diploid cells, 46 chromosomes

25

What is the result of meiosis

-4 diploids, 23 chromosomes

26

What is crossing over?

Parts of non sister chromatids "cross over" each other and exchange segments of DNA

27

What is the result of crossing over?

-Each chromosomes picks up new genetic information from the other
-multiple crossovers can occur between 2 chromosomes, can creat infinite genetic possibilities

28

What is independent assortment

-homologous pairs of chromosomes seperated and sort themselves into daughter cells; shuffling of genes

29

What happens during independent assortment

-homologous pairs of chromosomes seperate at equator and move towards opposite poles of cell

30

What is gamete formation in males

-Meiosis 1 occurs and produces 2 cells, followed by meiosis 2 if there's enough nutrients for cell division
-4 cells within cytoplasm and organelles equally divide among them

31

What is the gamete formation in females

Meiosis 1 occurs and produces 2 egg cells, unequal division of cytoplasm and organelles
After meiosis 2, threes egg cells disintegrate, one large egg cell remains most of cytoplasm, available for fertilization

32

Describe chromosome mutations in meiosis

-parts of chromosome can be inverted,
-parts of chromosome can be duplicated
-parts of chromosome can be lost or deleted
-parts of chromosome came move to a different region in the chromosome

33

When do chromosome mutations occur?

-cells exposed to mutagens (radiations or chemicals)

34

Describe mutations in meiosis 1 and meiosis 2

Meiosis 1: homologous chromosomes fail to seperate

Meiosis 2: sister chromatids fail to seperate

35

What is the result of mutations

-one gamete will have two copies of chromosomes, other will have no copy of that chromosome

36

What is a karotype?

Photograph that shows number of chromosomes a person has, the size, shape

37

What is karotypes for

Used to diagnose genetic disorders

38

How are karotypes prepared?

Cutting and pasting chromosomes from body cells during mitosis

39

How are homologous chromosomes identified (karotypes)

-paired by size, centromere location and banding patterns

40

What is a syndrome and give an example.

Particular disease or disorder with a specific group of symptoms that occur together

Down syndrome

41

Describe people diagnosed with Down syndrome

-characteristic facial features, -
-shortie stature
-prone to develope heart defects and disease (Alzheimer's, leukaemia)

42

What percent of people are caused by extra 21 chromosomes

95%

43

What's is sexual reproduction

-Requires 2 parents
-produces offspring genetically different from parent or any member of the same species m