Gene Editing

Question 1

CRISPR Abbreviation

Answer 1

Clustered: The repeats are grouped together in DNA sequences

Regularly Interspaced: The repeats are separated consistently by spacers

Short: Each repeat is a relatively short sequence of DNA nucleotides

Palindromic: Each sequence has parts which can be read the same forwards and backwards

Repeats: The same base sequence occurs several times in one part of the genome

Question 2

Conserved and Highly Conserved Sequences

Answer 2

Conserved: Identical or similar across a species or group of species

Highly Conserved: Identical or similar along long period of evolution

Question 3

Types of Gene Mutation

Answer 3

Beneficial: A mutation that provides an individual with a better chance of survival and is likely to be passed onto future generations

Detrimental: A mutation that causes disease or death and is less likely to be passed onto future generations

Question 4

Causes of Mutation

Answer 4

DNA Replication might not have good proofreading

Ionizing Radiation

Viruses can integrate their genetic material into the host DNA which disrupts host genes

Exposure to environmental toxins or industrial chemicals or pollutants

Question 5

Role of Genes (Alleles) in Variation

Answer 5

Genes come in different forms called alleles which have slight variations in DNA sequences, and organisms inherit their parent’s alleles. Due to the different combinations of alleles, they will promote variation as they receive different combinations from each parent

Question 6

Germ Cell Mutation VS Somatic Cell Mutation

Answer 6

Somatic occurs in body cells
Germ occurs in reproductive organs

Somatic is not passed onto offspring
Germ is passed onto offspring

Somatic can lead to health issues or diseases
Germ can directly affect offspring and all cells developed from the mutated zygote

Somatic is common
Germ is rare

Question 7

Purpose of Gene Knockout

Answer 7

Study the function of genes

Study biological pathways

Study mechanisms of certain drugs

Study of embryo development

Disease research

Question 8

Benefits of CRISPR-Cas9 Gene Editing

Answer 8

Precise as it cuts DNA at a specific location with high accuracy

Versatile as it can be used for various editing tasks such as inserting deleting or modifying genes

Efficient as it works quickly and easily compared to other gene editing tools

Question 9

Types of Base Substitution Mutations

Answer 9

Silent: Does not alter the amino acid sequence of the polypeptide, and occurs because of degenerate genetic code where multiple codons code for the same amino acid, which leads it to be unchanged

Missense: Causes the expression of a different amino acid

Nonsense: Adds a stop codon to the premature protein and stops protein synthesis

Question 10

Variation

Answer 10

The difference in phenotypes within the same species, and usually results from small differences in DNA base sequences

Question 11

Usage of CRISPR Good Way

Answer 11

Scientists can make their own RNA that Cas9 can cut, using this, they can:

Insert a new piece of DNA
Remove unwanted DNA
Make slight changes to DNA

Question 12

Functional Requirements of Highly Conserved Sequences

Answer 12

Highly conserved sequences probably code for essential proteins that are critical for organisms across species, and any slight change in these sequences could be detrimental which explains their strong conservation throughout evolution

Question 13

Applications of Gene Editing

Answer 13

Correcting genetic diseases

Developing new therapies for cancer and other illnesses

Engineering crops with desirable traits like resistance to pests or diseases

Question 14

Why are Some DNA Regions Highly Conserved

Answer 14

They have slower lates of mutation

Control gene expression

Code for proteins that are vital for life

Provide structural stability

Question 15

Mutations Classifications

Answer 15

Point Mutations: Base substitution
Frameshift Mutations: Insertion and Deletion

Question 16

Gene Mutation

Answer 16

A permanent random change in the base sequence of a gene, which produces a protein that has different properties

Question 17

Randomness in Genetic Mutation

Answer 17

Uncoiled DNA has a higher probability of encountering mutations as it is more exposed

Non-coding regions also have many mutations

Mutation Hotspots are regions where mutations are more frequent. An example is when cytosine is followed by guanine: CG

Question 18

Process of Crispr-Cas9 formation

Answer 18

Virus tries to invade bacteria

Bacteria fights back and grabs a fragment of virus DNA

The bacteria stores this snippet as a CRISPR sequence in its DNA

Over time, the bacteria collects many CRISPR sequences from different viruses forming a library

If the same virus attacks again, the bacteria recognizes it from its library and uses CRISPR sequence to guide Cas9 to virus’ DNA to cut the viral DNA

Question 19

Ethical Considerations of Gene Editing

Answer 19

Very expensive which limits access to those who need them most

Can have unintended side effects due to off target edits

Editing germ cells can pass change to future generations

Question 20

Gene Knockout

Answer 20

Inactivating a specific gene to observe the effect of its inactivation to find out about its function

Question 21

What is Used to Check Non-disjunction

Answer 21

Karyogram