Bio

Question 1

What is a genome?

Answer 1

All the DNA in a cell

A genome encompasses both coding and non-coding regions of DNA.

Question 2

How is DNA arranged in eukaryotic cells?

Answer 2

On linear DNA, specifically on independent chromosomes

Eukaryotic cells have multiple linear chromosomes.

Question 3

How is DNA arranged in prokaryotic cells?

Answer 3

On circular DNA

Prokaryotic cells typically possess a single circular chromosome.

Question 4

What types of genes can a genome include?

Answer 4

• Genes that code for proteins
• Regulatory genes
• Mitochondrial circular DNA
• Chloroplast circular DNA
• Genes for antibiotic resistance
• Viral RNA or DNA

Each type of gene plays a different role in cellular functions and organismal traits.

Question 5

What do regulatory genes code for?

Answer 5

Transcription factors, siRNAs, and miRNA

Regulatory genes are crucial for the control of gene expression.

Question 6

What does mitochondrial circular DNA code for?

Answer 6

Proteins involved in aerobic respiration

Mitochondrial DNA is inherited maternally in most organisms.

Question 7

What does chloroplast circular DNA code for?

Answer 7

Proteins involved in photosynthesis

Chloroplasts are found in plant cells and some protists.

Question 8

Where can genes that code for antibiotic resistance be found in prokaryotes?

Answer 8

On plasmids

Plasmids are small, circular DNA molecules independent of chromosomal DNA.

Question 9

What type of genetic material is found inside the capsid of a virus?

Answer 9

Viral RNA or DNA

The capsid protects the viral genetic material and aids in its transmission.

Question 10

What is the purpose of using reverse transcriptase in DNA isolation?

Answer 10

To make cDNA copies from mRNA templates

Reverse transcriptase carries out transcription in reverse.

Question 11

What are the steps involved in creating cDNA from mRNA using reverse transcriptase?

Answer 11

1. Mix mRNA with free DNA nucleotides and reverse transcriptase
2. Nucleotides bind to mRNA via complementary base pairing
3. Reverse transcriptase joins DNA nucleotides to form cDNA
4. DNA polymerase makes cDNA double stranded

This process converts mRNA into complementary DNA.

Question 12

What are restriction endonucleases?

Answer 12

Enzymes that hydrolyse DNA at specific base sequences called ‘restriction sites’

They cut DNA at specific locations to isolate fragments containing desired genes.

Question 13

What is a characteristic feature of the sequences recognized by restriction endonucleases?

Answer 13

They are often palindromic

A palindromic sequence reads the same in opposite directions.

Question 14

How do restriction endonucleases hydrolyse DNA?

Answer 14

They hydrolyse the DNA’s phosphodiester bonds at specific restriction sites

This creates fragments of DNA containing the desired genes.

Question 15

What is the role of DNA polymerase in the cDNA synthesis process?

Answer 15

To make cDNA double stranded

It is required after reverse transcriptase has formed a single stranded cDNA molecule.

Question 16

Fill in the blank: The process of converting mRNA into cDNA is called _______.

Answer 16

Reverse transcription

This process involves using reverse transcriptase.

Question 17

What is the initial step in isolating a specific DNA fragment?

Answer 17

Conversion of mRNA to complementary DNA (cDNA)

Other methods include using restriction enzymes or creating genes in a ‘gene machine’.

Question 18

True or False: Different restriction endonucleases hydrolyse DNA at the same specific restriction sites.

Answer 18

False

Each restriction endonuclease has a unique active site that is complementary to specific DNA sequences.

Question 19

What is the function of a ‘gene machine’ in DNA fragment isolation?

Answer 19

To create the gene synthetically

This is one of the methods for producing specific DNA fragments.

Question 20

What are the two types of ends produced by restriction enzymes?

Answer 20

Blunt ends and sticky ends

Blunt ends are typically used in PCR and gel electrophoresis, while sticky ends are used in insertion.

Question 21

Which restriction enzyme is known for producing blunt ends?

Answer 21

Alu1

Alu1 is a restriction enzyme that produces blunt ends.

Question 22

Which restriction enzyme is known for producing sticky ends?

Answer 22

EcoR1

EcoR1 is a restriction enzyme that produces sticky ends.

Question 23

What is the ‘gene machine’ used for?

Answer 23

Manufacturing genes in a lab

The gene machine synthesizes DNA fragments based on desired nucleotide sequences entered into a computer.

Question 24

How can a nucleotide sequence be reverse engineered from a protein?

Answer 24

By determining the primary structure (amino acid sequence) of the protein and then deducing the nucleotide sequence

This process involves translating the amino acid sequence back to the corresponding mRNA and then to DNA.

Question 25

What are some advantages of using mRNA in gene synthesis?

Answer 25

* Easy to isolate from cells * Introns have been removed * Can be inserted into bacteria * Thousands of restriction endonucleases are available * Faster process due to automated machinery * Sequences contain no introns * Can reverse engineer from protein structure ## Footnote These advantages facilitate the gene synthesis process and enhance efficiency.

Question 26

What are some disadvantages of gene synthesis?

Answer 26

* Many steps involving enzyme-controlled reactions * Time consuming * Requires more technical expertise * Contains introns * Enzymes may cut in the middle of the desired gene * Requires the primary structure of the polypeptide ## Footnote These disadvantages can complicate the gene synthesis process and affect the functionality of proteins produced.

Question 27

Fill in the blank: The _______ is a method to produce specific DNA sequences by entering desired nucleotide bases into a computer.

Answer 27

gene machine ## Footnote The gene machine automates the synthesis of DNA fragments.

Question 28

True or False: Sticky ends are used in PCR.

Answer 28

False ## Footnote Blunt ends are used in PCR, while sticky ends are used for insertion.

Question 29

What is one potential issue with enzymes during gene synthesis?

Answer 29

Enzymes may cut in the middle of the desired gene, leading to a non-functional protein ## Footnote This can disrupt the integrity of the gene being synthesized.

Question 30

List the steps to reverse engineer a desired nucleotide sequence from a protein.

Answer 30

* Determine the primary structure of the polypeptide * Translate to mRNA * Convert mRNA to DNA ## Footnote This process allows for the reconstruction of DNA sequences based on known protein structures.

Question 31

Steps of how restriction endonucleases work?

Answer 31

•DNA sample incubated with specific restriction endo-:hydrolyse DNA’s phosphodiester bonds into fragments wherever the ‘restriction site’ appears •if target gene has recognition sequences before and after the target gene-fragment contain desired gene

Question 32

Steps involved in gene machine

Answer 32

Enter the desires sequence of nucleotide bases into computer and synthesising the DNA fragments using automated machinery

Question 33

Define prompter region

Answer 33

Allow transcription factors to bind

Question 34

Define terminator region

Answer 34

Cause transcription of gene of interest to stop

Question 35

What is a vector in the context of DNA insertion?

Answer 35

A DNA carrier, such as a bacterial plasmid or virus, used to transfer foreign DNA into cells.

Question 36

What is the first step in inserting isolated DNA fragments into a vector?

Answer 36

Isolated Target DNA fragment is inserted into the vector DNA by cutting open the vector DNA using the SAME restriction endonuclease.

Question 37

What are 'sticky ends'?

Answer 37

Complementary ends produced between the ends of DNA fragments and cut ends of vector DNA.

Question 38

How does the target DNA fragment attach to the vector DNA?

Answer 38

By complementary base pairing between their 'sticky ends'.

Question 39

What enzyme is used to join the DNA fragment and vector DNA?

Answer 39

DNA ligase.

Question 40

What is the process called when DNA ligase joins the DNA fragment and vector DNA?

Answer 40

Ligation.

Question 41

What type of bonds are formed during the ligation process?

Answer 41

Phosphodiester bonds.

Question 42

What is recombinant DNA?

Answer 42

The new combined DNA fragment and vector DNA.