unit 4 genetics

Question 1

Nucleic Acid

Answer 1

The macromolecule that holds our genetic material (DNA).

Question 2

Nucleotide

Answer 2

Make up nucleic acids (the monomer).

Question 3

Chromosome

Answer 3

tightly coiled strands of DNA.

Question 4

Gene

Answer 4

A section of DNA that has instructions to code for a protein.

Question 5

RNA primer

Answer 5

a short segment of single-stranded RNA used as a binding site for DNA polymerase to initiate DNA replication.

Question 6

Okazaki fragments

Answer 6

small sections of DNA that are formed during discontinuous synthesis of the lagging strand during DNA replication.

Question 7

Use a Venn diagram to compare and contrast DNA and RNA.

Answer 7

DNA: Deoxyribose sugar, Thymine, Double helix, Doesn’t leave the nucleus.
Both are made of nucleotides, and share adenine, guanine, and cytosine.
RNA: Ribose sugar, Uracil, Single strand, Can leave the nucleus and go into cytoplasm

Question 8

Explain the base pairing rules of DNA. Provide an example of a strand of DNA with its complementary strand.

Answer 8

Nitrogen bases bond only to their complementary base pair with hydrogen bonds like A to T and C to G. This is called complementary base pairing rules

Question 9

Draw the structure of a nucleotide and label the parts.

Answer 9

draw on paper

Question 10

Describe the difference between purines and pyrimidines including which nitrogen bases are which.

Answer 10

The difference between purines and pyrimidines is that purines have a big base and it has adenine and guanine as their bases. Pyrimidines have a small base and it has thymine and cytosine as their base pairs.

Question 11

Explain, in detail, the structure of a DNA molecule.

Answer 11

DNA is a double helix and the sugar and phosphates make up the sugar phosphate backbone. In the middle, there are nitrogen bases with weak hydrogen bonds. Nitrogen bases bond with each other (A with T and C with G).

Question 12

Summarize the process of DNA replication, including the enzymes involved, and explain the significance of the process.

Answer 12

When it is ready to divide it has to make a copy of itself and has to have an identical copy of the DNA. This event happens in the nucleus during S-phase. The enzymes that are involved are helicase and DNA polymerase. Helicase unzips the DNA into two strands while DNA polymerase adds complementary nucleotides to the template strand.

Question 13

Describe the difference between the leading strand and the lagging strand.

Answer 13

A leading strand is when a new strand is made towards the replication fork. This needs one RNA primer created from primase and this happens continuously. A lagging strand is when a new strand synthesis is away from the replication fork. This replicates discontinuously which creates Okazaki fragments. Okazaki fragments are joined by DNA ligase and need multiple RNA primers from primase.

Question 14

Explain why DNA replication is considered to be semi-conservative.

Answer 14

DNA replication is considered to be semi-conservative because it uses its old pattern or template and grabs a new one to join with it.

Question 15

Protein synthesis

Answer 15

The process of reading the instructions in DNA to make a polypeptide.

Question 16

Polypeptides

Answer 16

A chain of amino acids: that can bind to others and fold into a protein.

Question 17

Transcription

Answer 17

DNA is copied into a complementary strand of mRNA.

Question 18

Introns

Answer 18

Non-coding regions.

Question 19

Exons

Answer 19

Coding regions.

Question 20

Genetic Code

Answer 20

Code of instructions for how to make proteins.

Question 21

Codon

Answer 21

A set of 3 nucleotides on the mRNA.

Question 22

Anticodon

Answer 22

Complementary 3 nucleotides of tRNA.

Question 23

Amino Acid

Answer 23

Monomer (building block for making proteins, held together by peptide bonds).

Question 24

Translation

Answer 24

Interpreting the RNA message into a polypeptide to make a protein.

Question 25

Epigenetics

Answer 25

The study of changes in gene expression that are heritable.

Question 26

Explain the central dogma and why a two-step process is necessary in order to make proteins.

Answer 26

The central dogma is how DNA can leave the nucleus. This process happens in a two-step process.

Question 27

Describe the roles of the three essential types of RNA in protein synthesis. Include a sketch to represent each one.

Answer 27

The three types of RNA are tRNA, mRNA, and rRNA. What tRNA does is that it transfers amino acids. mRNA copies instructions in DNA and carries them to the ribosomes in the cytoplasm. rRNA makes up the ribosomes.

Question 28

Summarize, in detail, the steps of transcription and translation. Include the location of each process and the enzymes involved.

Answer 28

Transcription: RNA binds to a DNA promoter and transcription begins, it will then unzip the gene that will be copied. RNA polymerase will use complementary base pairs and will match the RNA nucleotides with the exposed DNA nucleotides. It then releases the mRNA molecule. The DNA zips back up and it leaves the nucleus to go to the cytoplasm

Translation: mRNA attaches to a small subunit of the ribosome and the ribosome reads the codons of the mRNA in 5’ to 3’ starting with the AUG codon. tRNA comes into the mix and picks up and drops off the amino acids to its correspondent. This will create polypeptide bonds and this all stops when it reaches the stop codon.

Question 29

Transcribe and translate the following strand of DNA (TACACCGGAGCGTTTATT)

Answer 29

Transcribe: AUGUGGCCUCGCAAAUAA
Translation: AUG UGG CCU CGC AAA UAA

Question 30

Explain how the mRNA is modified after transcription.

Answer 30

It is modified after transcription by being read through codons. This will then be modified into an amino acid-forming protein.

Question 31

Describe an example of how gene expression is regulated.

Answer 31

An example of gene expression is HIV. This works by turning on and off.

Question 32

Explain the difference between epigenetics and mutations.

Answer 32

Epigenetics are heritable changes, unlike mutations. Mutations are changes in the genes that alter the process.