DNA

Question 1

What is complementary base pairing?

Answer 1

A-T, A-U, G-C

This refers to the specific pairing of nitrogenous bases in nucleic acids.

Question 2

What types of bonds are found within a DNA molecule?

Answer 2

Covalent bonds and hydrogen bonds

Covalent bonds link the sugar and phosphate backbone, while hydrogen bonds connect the base pairs.

Question 3

What is the process of DNA replication?

Answer 3

The process by which DNA makes a copy of itself prior to cell division

Involves unwinding the double helix, complementary base pairing, and synthesizing new strands.

Question 4

What are the main differences between RNA and DNA?

Answer 4

RNA is single-stranded, contains uracil instead of thymine, and has ribose sugar; DNA is double-stranded and has deoxyribose sugar

These differences impact their functions in the cell.

Question 5

What are the two main processes of gene expression?

Answer 5

Transcription and Translation

Transcription converts DNA to mRNA, while translation synthesizes proteins from mRNA.

Question 6

What is the outcome of transcribing a section of DNA into mRNA?

Answer 6

The creation of a complementary RNA strand

The mRNA sequence is complementary to the DNA template strand.

Question 7

What are the functions of mRNA and tRNA?

Answer 7

mRNA carries genetic information from DNA to ribosomes; tRNA transports amino acids to the ribosome during protein synthesis

Both play crucial roles in translating genetic code into proteins.

Question 8

How many nucleotides are required to produce a protein with a certain number of amino acids?

Answer 8

Three nucleotides per amino acid

Therefore, for n amino acids, 3n nucleotides are needed.

Question 9

What is the relationship between a DNA triplet, mRNA codon, and tRNA anti-codon?

Answer 9

DNA triplet transcribes to mRNA codon and translates to tRNA anti-codon

This illustrates the flow of genetic information from DNA to protein.

Question 10

Given a DNA sequence, how do you determine the resulting amino acid sequence?

Answer 10

Translate each mRNA codon into its corresponding amino acid

This requires knowledge of the genetic code.

Question 11

What are the five main questions regarding mutations?

Answer 11

Types, causes, effects, repair mechanisms, and implications for evolution

Understanding these aspects is crucial for genetics and molecular biology.

Question 12

What is recombinant DNA?

Answer 12

DNA that has been artificially formed by combining constituents from different organisms

This technique is widely used in genetic engineering.

Question 13

What does metastasis refer to?

Answer 13

The spread of cancer cells from the original tumor to other parts of the body

This is a key factor in cancer progression and severity.

Question 14

What are the characteristics of cancer cells?

Answer 14

Uncontrolled growth, invasion of surrounding tissues, and ability to metastasize

These traits distinguish cancer cells from normal cells.

Question 15

What enzymes are involved in DNA replication?

Answer 15

DNA helicase, DNA polymerase, and DNA ligase

These enzymes play critical roles in unwinding, synthesizing, and joining DNA strands.

Question 16

If a chromosome has a certain percentage of guanine, what percentage of adenine does it have?

Answer 16

The percentage of adenine equals the percentage of thymine, which is equal to the percentage of cytosine

This follows Chargaff’s rules of base pairing.

Question 17

What is CRISPR?

Answer 17

A gene-editing technology that allows for precise alterations in DNA sequences

CRISPR is based on a natural defense mechanism found in bacteria.

Question 18

What is the role of DNA helicase?

Answer 18

To unwind the DNA double helix during replication

This is the first step in preparing the DNA for copying.

Question 19

What is the function of DNA polymerase?

Answer 19

To synthesize new DNA strands by adding nucleotides to a growing chain

It also has proofreading abilities to ensure accuracy.

Question 20

What is the significance of transcription factors?

Answer 20

Proteins that help regulate the transcription of specific genes

They play a crucial role in cell differentiation and response to signals.

Question 21

What is the genetic code?

Answer 21

The set of rules by which information encoded in mRNA is translated into proteins

It consists of codons, each corresponding to an amino acid.

Question 22

What are codons?

Answer 22

Three-nucleotide sequences on mRNA that correspond to specific amino acids

Codons are crucial for translating genetic information into proteins.

Question 23

What is an anti-codon?

Answer 23

Three-nucleotide sequence on tRNA that pairs with a complementary mRNA codon

This ensures the correct amino acid is added during translation.

Question 24

What is the start codon?

Answer 24

AUG

This codon signals the beginning of translation and codes for methionine.

Question 25

What role does ribosomal RNA (rRNA) play?

Answer 25

It forms the core of the ribosome's structure and catalyzes protein synthesis ## Footnote rRNA is essential for translating mRNA into a polypeptide chain.

Question 26

What is the purpose of splicing in mRNA processing?

Answer 26

To remove introns and join exons together ## Footnote This process creates a mature mRNA molecule ready for translation.

Question 27

What are the potential consequences of mutations?

Answer 27

Altered protein function, disease, or no effect ## Footnote Some mutations can lead to beneficial adaptations, while others can cause disorders.

Question 28

What is a silent mutation?

Answer 28

A change in the nucleotide sequence that does not alter the amino acid sequence ## Footnote These mutations occur due to the redundancy of the genetic code.

Question 29

What is a missense mutation?

Answer 29

A mutation that results in a different amino acid being incorporated into a protein ## Footnote This can affect protein function depending on the properties of the amino acid.

Question 30

What is a nonsense mutation?

Answer 30

A mutation that creates a premature stop codon in the protein sequence ## Footnote This typically leads to nonfunctional proteins.

Question 31

What is the role of ligase in DNA replication?

Answer 31

To join Okazaki fragments on the lagging strand ## Footnote Ligase is essential for creating a continuous DNA strand.

Question 32

What is the central dogma of molecular biology?

Answer 32

DNA → RNA → Protein ## Footnote This summarizes the flow of genetic information within a biological system.

Question 33

What are the three sites of the ribosome during translation?

Answer 33

A site (aminoacyl), P site (peptidyl), and E site (exit) ## Footnote These sites facilitate the addition of amino acids and the release of tRNA.

Question 34

What is gene therapy?

Answer 34

A technique that modifies a gene to treat or prevent disease ## Footnote This can involve replacing, inactivating, or introducing genes into cells.

Question 35

What are restriction enzymes?

Answer 35

Proteins that cut DNA at specific sequences ## Footnote They are essential tools in molecular cloning and genetic engineering.

Question 36

What is the role of the promoter in gene expression?

Answer 36

To initiate transcription of a gene ## Footnote The promoter is a specific DNA sequence recognized by RNA polymerase.

Question 37

What is a frameshift mutation?

Answer 37

A mutation caused by insertions or deletions that alters the reading frame of the genetic code ## Footnote This can lead to completely different and often nonfunctional proteins.

Question 38

What is the significance of genetic diversity?

Answer 38

It allows populations to adapt to changing environments and contributes to evolution ## Footnote Genetic diversity is crucial for the survival of species.

Question 39

What is a genetic marker?

Answer 39

A gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species ## Footnote Genetic markers are useful in genetic mapping and studies of inheritance.

Question 40

What is the function of transcription in protein synthesis?

Answer 40

To create an RNA copy of a gene's DNA sequence ## Footnote This is the first step in the process of translating genetic information into proteins.

Question 41

Angiogenesis

Answer 41

Cancers release growth factor to neighbouring blood vessel to branch into the cancer