RAI — 3B — Inheritance, cell division, variation, mutations & evolution

Question 1

Genome?

Answer 1

All genetic information (DNA) of an organism

Question 2

Gene?

Answer 2

a section of DNA that codes for a specific Protein to influence specific characteristics
Can code for structural protein such as skin
Or can code for functional protein like haemoglobin

Question 3

Chromosome?

Answer 3

A tightly coiled molecule of DNA in a condensed mass

Question 4

Nucleus?

Answer 4

Contains chromosomes made of genes in the DNA

Question 5

Allele?

Answer 5

Different version of the same gene (e.g. hair colour is a gene. Brown hair is an allele of the hair gene)

Question 6

dominant?

Answer 6

Only one copy of this allele is needed to show the characteristic

Question 7

recessive?

Answer 7

Needs two copies of the allele to show the characteristic

Question 8

Heterozygous?

Answer 8

1 copy of each type of allele (e.g. Tt)

Question 9

homozygous?

Answer 9

2 copies of the same allele
e.g. TT — homozygous dominant
tt — homozygous recessive

Question 10

phenotype?

Answer 10

The characteristic/trait that is shown/expressed (can roll their tongue)

Question 11

genotype?

Answer 11

The combination of alleles you have (Rr)

Question 12

Pedigree shapes and colors:

Answer 12

Circle — female
Square — male
Black — have
White — don’t have

how to remember:
females have a CIRCLE hole
3amo osama has a SQUARE face
black people HAVE dark skin
white people DON’t have dark skin

Question 13

How to know if it is dominant or recessive in a pedigree?

Answer 13

Dominant traits are likely to be in every generation

Recessive traits are likely to skip generations

Question 13

How is gender controlled by one pair of chromosomes?

Answer 13

Females possess two copies of the X Chromosome (XX)
Males possess one X and a shorter Y Chromosome (XY)

how to remember:
females get two kisses when you salam
only one man gets a kiss because you only marry one

Question 14

DNA

Answer 14

Genetic material that gives information about how cells should function

Base pairs held together by hydrogen bonds:
A-T (Adenine, Thymine)
C-G (cytosine, guanine)

Question 15

Monohybrid?

Answer 15

1 gene determines 1 characteristic
- Eye color
- Hair color
^Discontinuous variation (unaffected by environment, distinct categories)

Question 16

Polygenic?

Answer 16

Many genes determine a characteristic
- Height
- Skin color
^Continuous variation (influenced by environment, no distinct categories)

Question 17

Diploid?

Answer 17

Contains two complete sets of chromosomes
23 pairs, 46 in total
Diploid – Double

Question 18

Haploid?

Answer 18

Contain only one set of chromosomes
23 in total
HAploid — HAlf

Question 19

Mitosis

Answer 19

Cell Division that produces two genetically identical, diploid daughter cells

how to remember:
mitosis (my toe sis) = identical daughter cells

Question 20

Function of mitosis

Answer 20

• tissue repair
• growth
• asexual reproduction
• development (zygotes undergo mitosis to develop into embryos)

Question 21

Process of mitosis

Answer 21

1. DNA replication to form two copies of each chromosome in the cell (now it has 46 pairs of chromosomes)
2. Then mitosis occurs and the cell splits into two daughter cells
3. each daughter cell has 23 pairs of identical chromosomes (diploid)

Question 22

meiosis?

Answer 22

produces four haploid gamete cells (reproductive cells — egg and sperm) that are not genetically identical

Question 23

function of meiosis?

Answer 23

• for reproduction, haploid cells are needed to to contain only one copy of each chromosome (egg (23) + sperm (23) = zygote (43))

Question 24

process of meiosis

Answer 24

1. meiosis has two stages of division
2. chromosomes in a parent cell make identical copies of themselves
3. similar chromosomes pair up and sections of dna are swapped
4. pairs of chromosomes divide
5. then they divide again to make four haploid cells

Question 25

Variation?

Answer 25

Differences in between individuals particularly in the same species
- Can be genetic (eye/hair color, blood type, inherited disorders) or environmental (envir. conditions (temp, weather), predators/pathogens, presence of food) or both

Question 26

Mutation?

Answer 26

a rare, random change in genetic material that can be inherited.

Question 27

Natural selection?

Answer 27

VOSSIG
V — variation (individuals within a species differ. Caused by mutation)
O — over-production (all organisms over-produce which limits the number of resources available)
S — struggle for existence (not enough resources)
S — survival of the fittest (one with the mutation survives)
I — Inherit (the ones who survive reproduce and pass down their alleles)
G — gradual change (happens over many generations)

Question 28

Antibiotic resistance?

Answer 28

-You start taking an antibiotic
-Some bacteria are susceptible to (killed by) the antibiotic. Some are resistant to (not killed by) antibiotic
-The susceptible (weak) bacteria are killed first
-Only resistant (strong) bacteria are left
-You stop taking the antibiotic
-The resistant (strong) bacteria reproduce
-The resistant (strong bacteria are now more common
- If you take the antibiotic again, it won’t work because all the bacteria are resistant

Question 29

Cell division process names

Answer 29

1. Prophase - chromosomes replicate
2. Metaphase - middle (chromosomes line up in the middle)
3. Anaphase - chromosomes move away from each other
4. Telophase - two new cells form
5. For meiosis it does steps 1-4 twice