40S Unit 3 - Genetic Code Mutations

Question 1

what is a genetic mutation

Answer 1

changes in DNA bases which affect protein synthesis

Question 2

how do people have genetic mutations

Answer 2

they are born with them but inheritance factors and environmental factors determine whether or not a child will have a genetic mutation

Question 3

what are environmental factors that cause mutagens called and give examples

Answer 3

they are called mutagens and some examples are:
- UV light
- drugs
- alcohol
- radioactivity
- polychlorinated biphenyls (PCBs)
- persistent organic pollutants (POPs)

Question 4

what types of DNA code mutations are there

Answer 4

1. point mutation
2. frameshift mutation
3. dimer mutation

Question 5

what happen during a point mutation

Answer 5

one base is substituted for another in the DNA code resulting in little or no change in amino acids produced

Question 6

list and explain the 3 types of point mutations

Answer 6

1. missense mutation - codes for a different amino acid
2. silent mutation - codes for the same amino acid
3. nonesense mutation - codes for a stop codon

Question 7

explain what a frameshift mutation is

Answer 7

the addition and/or deletion of bases occurring at more than one site in the original DNA sequence, resulting in a large number of changes in the amino acids produced

frameshift mutations often result in serious alterations in an organism’s development and appearance

Question 8

explain what happens during dimer formation mutations

Answer 8

some substances such as mercury, drug, radioactivity or just bad luck can cause a bond to form between adjacent bases making it impossible for mRNA to transcribe the code

Question 9

what is a chromosome mutation

Answer 9

any change in the structure or arrangement of chromosomes

Question 10

when do chromosome mutations mostly happen

Answer 10

during the crossing over stage of meiosis

Question 11

list and explain the types of chromosome mutations

Answer 11

1. translocation - the transfer of a piece of one chromosome to another chromosome
2. inversion - a region of DNA on the chromosome can flip its orientation with respect to the rest of the chromosome
3. deletion- a large section of a chromosome can be deleted resulting in the loss of a number of genes
4. duplications - some genes are duplicated and displayed twice on the same chromosome
5. non-disjunction - when spindle fibers fail to separate during meiosis resulting in gametes with one extra chromosome and other gametes lacking a chromosome

Question 12

which chromosome mutation is most likely to cause evolutions of new genes?

Answer 12

duplication

Question 13

which chromosome mutation causes chronic myelogenous leukemia (CML)

Answer 13

translocation as the chromosome 9 and 22 swap portions of their chromosomes during meiosis

Question 14

list 3 syndromes that can occur due to non-disjunction

Answer 14

down’s syndrome
turners syndrome
klinefelter syndrome

Question 15

most chromosome mutations result from _____________________

Answer 15

non-disjunction

Question 16

how does Down’s Syndrome occur

Answer 16

non-disjunction occurs in chromosome 21 of a human egg cell causing their cells to have 47 chromosomes instead of 46

because of this it is also called Trisomy 21

Question 17

what happens in Turners Syndrome

Answer 17

all of part of one X chromosome is missing

Question 18

what happens in Klinefelter Syndrome

Answer 18

an additional X chromosome in males resulting in XXY

Question 19

state and explain the ways chromosome mutations can be detected

Answer 19

1. amniocentesis - karyotype of cells in amniotic fluid
2. chorionic villus sampling - testing the uterus lining tissue
3. fetal blood sampling

Question 20

when did the Human Genome Project start and end

Answer 20

began in 1990 and was completed in 2003

Question 21

what does the Human Genome Project allow u do

Answer 21

the entire human genome is mapped and sequenced and because all life shares the same 4 base DNA codes, it makes it easy to take genes from one species and splice (insert) them into another. it also lets us compare DNA sequences and detect mutations

Question 22

what is genetic engineering

Answer 22

the alteration of the genetic material of an organism

Question 23

how can genetically modified organisms be created

Answer 23

1. adding a foreign gene
2. altering an existing gene
3. delete or “turn off” a gene

Question 24

list the top 10 genetically modified foods

Answer 24

1. corn
2. soy
3. cotton
4. papaya
5. rice
6. canola
7. potatoes
8. tomatoes
9. dairy products
10. peas

Question 25

what are restriction enzymes

Answer 25

they allow genetic engineers cut DNA in a controlled way at very precise recognition sites

Question 26

by using a tool kit of over _____ restriction enzymes recognizing about ____ recognition sites, genetic engineers are able to ‘cut’ and ‘paste’ DNA from any type of organism

Answer 26

400
100

Question 27

some restriction enzymes cut leaving an overhang of a single stranded DNA called ______________

Answer 27

sticky ends

Question 28

DNA cut in such a way that produces ends which may only be joined to other sticky ends with a ________________ ____________ ______________

Answer 28

complementary base sequence

Question 29

what is ligation

Answer 29

when DNA fragments produced using restriction enzymes are reassembled using an enzyme called DNA ligase

Question 30

what is recombinant DNA

Answer 30

DNA of different origins that has been recombined

Question 31

what is annealing

Answer 31

when 2 matching sticky ends from DNA fragments of different sources come together and are joined by base pairing
the joined fragments form a linear molecule or a circular one

Question 32

if 2 DNA fragments are going to be joined together, are they cut from different restriction enzymes or the same restriction enzyme

Answer 32

the same restriction enzyme as the DNA will be of different origins but are cut using the same restriction enzyme

Question 33

what are some uses of recombinant DNA

Answer 33

• plants (RoundUp Ready plants, FlavrSavr tomato)
• animals (spider goat, oversized salmon, phosphate reduced pigs)
• bacteria (insulin, human growth hormone (HGH), bioremediation)
• gene pharming (using animals to produce pharmaceuticals)

Question 34

how is human insulin and human growth hormone produced

Answer 34

1. the gene for human insulin is isolated from human cells and inserted into plasmids
2. the plasmids are introduced into bacterial cells which manufacture the insulin protein based on the human code
3. the purified product is identical in nature to human insulin and does not cause any allergies

Question 35

what characteristics can be derived from plants or other organisms that can be beneficial

Answer 35

• delayed fruit ripening for longer shelf life
• resistance to insects and plant viruses
• enhanced flavour and nutritional content
• edible vaccines to prevent widespread diseases in developing countries