B13 - Reproduction

Question 1

name:

both types of reproduction

Answer 1

sexual and asexual

Question 2

list 3:

factors of asexual reproduction

Answer 2

• 1 parent
• 2 cloned offspring of the parent
• cell division mitosis

Question 3

list 3:

factors of sexual reproduction

Answer 3

• 2 parent cells
• male and female gametes join (fuse)
• genetic variation in offspring

Question 4

name:

the process of how gametes are prodced

Answer 4

meiosis cell division

Question 5

define:

diploid number

Answer 5

the number of chromosomes in an organism’s body cell

e.g. human diploid number is 46

Question 6

define:

haploid number

Answer 6

the number of chromosomes in an organism’s gamete

e.g. human haploid number is 23

Question 7

define:

genetic code

Answer 7

the sequence of bases in DNA

Question 8

name:

complimentary base pairs

Answer 8

A = T
C ≡ G

“apples in the tree, cars in the garage”

Question 9

What does the genetic code do?

Answer 9

the sequence of bases codes for proteins

Question 10

define:

triplet code

in DNA

Answer 10

a sequence of 3 bases that code for a specifc amino acid

Question 11

What makes up a nucleotide?

Answer 11

• sugar
• phosphate group
• base
  image

Question 12

structural shape of DNA

Answer 12

double helix

Question 13

list 3:

stages of DNA replication

Answer 13

1. DNA helix unwinds
2. two strands seperate
3. new bases bond to each strand
   This forms 2 identical DNA helixes

Question 14

purpose of mRNA

Answer 14

messanger RNA strand leaves the nucleus which carry the coding sequence for proteins (transcripts). It is complimentary to the DNA

Question 15

purpose of RNA polymerase

Answer 15

enzyme that copies DNA to form mRNA

Question 16

purpose of tRNA

Answer 16

transfer RNA molecules made an anticodon that carry amino acids that binds to mRNA. releases amino acids to form chains called proteins

Question 17

name:

the difference between mRNA bases and DNA

Answer 17

T is replaced with U

Question 18

define:

codon

Answer 18

three bases

Question 19

describe:

protein synthesis

Answer 19

1. RNA polymearease enzyme uses DNA to form complimentary mRNA
2. mRNA leaves the nuclues
3. in the ribosome mRNA binds to an complimentary anticodon on a tRNA molecule
4. tRNA releases an amino acid
5. amino acids released bind together to form a long chain called a protein

Question 20

name:

two stages of protein synthesis and where they occur in a cell

Answer 20

1. transcription - nucleus
2. translation - ribosomes

Question 21

define:

phenotype

Answer 21

the observable characteristics of an organism

genotype + environmental effects

Question 22

define:

genotype

Answer 22

an organism’s complete set of genes

Question 23

define:

gene

Answer 23

a small section of DNA on a chromosome

Question 24

define:

alleles

Answer 24

different forms of the same gene

Question 25

When is a dominant allele expressed?

Answer 25

Always expressed if it is present

Question 26

When is a recessive allele expressed?

Answer 26

Only expressed when there are 2 copies present

Question 27

# define: homozygous

Answer 27

two identical alleles | example: AA or aa

Question 28

# define: heterozygous

Answer 28

two different alleles | example: Aa

Question 29

What is a punette square used for?

Answer 29

determining probabilities of characteristics of an offspring

Question 30

# define: chromosome

Answer 30

a long strand of DNA that codes for the characteristics of an organism

Question 31

# list 2: genetic disorders, dominant/recessive, what they cause

Answer 31

- polydactyly (dominant) - extra finger/toe - cystic fibrosis (recessive) - respiratorsy system clogged with mucus

Question 32

# define: zygote

Answer 32

fertilised egg cell

Question 33

# name: male and female genotype

Answer 33

XY and XX

Question 34

# list 3: methods to determine genetic disorders | at an early stage in life

Answer 34

- during pregnancy - blood samples from new born - Pre-implantation genetic diagnosis (PGD), during IVF

Question 35

# name: one disadvantage of genetic screening

Answer 35

false negatives / positives

Question 36

# list 3: advantages of *sexual* reproduction

Answer 36

- variation - possible adaptation to environment - human uses of selective breeding - disease less likely to affect all organisms

Question 37

# list 3: advantages of *asexual* reproduction

Answer 37

- only 1 parent needed - time and energy efficient as no need to find a mate - faster than sexual - many offspring produced in favourable conditions

Question 38

# list 2: disadvantages of *sexual* reproduction

Answer 38

- time and energy are needed to find a mate - not possible for an isolated individual

Question 39

# list 2: disadvantages of *asexual* reproduction

Answer 39

- no variation - no adaptation to environment - disease can wipe out organism

Question 40

# describe: stages of meiosis

Answer 40

1. chromosomes create copies and line up 2. diploid cell divides 3. each daughter cell divides again 4. 4 non-identical haploid cells are made, these are gametes