Ch.15 - DNA And RNA

Question 1

What is heredity?

Answer 1

Heredity is the passing on of features from parents to offspring through genes.

Question 2

What is a gene?

Answer 2

A gene is a section of DNA that causes the production of a protein.

Question 3

What is gene expression?

Answer 3

Gene expression is the way in which the genetic information in a gene is decoded in the cell and used to make a protein.

Question 4

What are characteristics?

Answer 4

Characteristics are traits that are inherited genetically.

Question 5

What is non-coding DNA?

Answer 5

Non-coding DNA is DNA that does not cause the production of a protein.

Question 6

What is the genetic code?

Answer 6

The genetic code is the sequence of bases in DNA that provide the instruction for a cell to form a protein.

Question 7

What is a triplet(codon)?

Answer 7

A codon is a sequence of 3 bases in DNA/RNA that act as a code for an amino acid.

Question 8

What is DNA profiling?

Answer 8

DNA profiling is the generation of a pattern of bands from a DNA sample.

Question 9

Describe the method to prepare a DNA profile.

Answer 9

The DNA is released from cells. The DNA is cut into fragments using restriction enzymes. The DNA fragments are separated according to size(by gel electrophoresis). The patterns produced are analysed.

Question 10

What is forensic medicine?

Answer 10

Forensic medicine is the way in which medical knowledge is used in legal situations.

Question 11

What is genetic screening?

Answer 11

Genetic screening is the testing of DNA for the presence or absence of a particular gene.

Question 12

Where does protein synthesis take place?

Answer 12

Protein synthesis takes place in the cytoplasm of the cell at the ribosomes.

Question 13

Describe the first stage of protein synthesis.

Answer 13

In initiation, the DNA double helix unwinds at the site of the gene using enzymes.

Question 14

Describe the second stage of protein synthesis.

Answer 14

Transcription is the making of mRNA using DNA as a template. mRNA is formed by mRNA nucleotides that enter the nucleus from the cytoplasm. These nucleotides align with the exposed bases of the DNA, RNA polymerase joins them. mRNA carries information from nucleus to ribosomes.

Question 15

Describe the third stage of protein synthesis.

Answer 15

Translation is the making of a protein using mRNA code. mRNA attaches to a ribosome. tRNA carries the correct amino acids back to the ribosome, and is connected using peptide bonds. tRNA joins with mRNA according to codons and anti codons. Translation ends when the stop codon is reached.

Question 16

Describe the 4th stage of protein synthesis.

Answer 16

Protein folding is when the chain of amino acids are folded into their functional shape.

Question 17

What do mRNA strands contain?

Answer 17

Each mRNA strand has a start codon, a series of codons for each of the amino acids in the protein to be formed and a stop codon.

Question 18

What is tRNA made of?

Answer 18

tRNA is made of a specific amino acid at one end and 3 bases at the other(anticodon triplet).

Question 19

What is rRNA?

Answer 19

rRNA along with protein make up ribosomes.

Question 20

What are nucleotides made of?

Answer 20

Nucleotides consist of a phosphate, sugar and nitrogen containing base. In DNA this is PO4, deoxyribose and ATC or G.

Question 21

What are the purines?

Answer 21

The purines are adenine and guanine.

Question 22

What are the pyrimidines?

Answer 22

The pyrimidines are thymine and cytosine.

Question 23

What is an anticodon?

Answer 23

An anticodon is a sequence of 3 bases on tRNA that are complementary to a sequence of 3 bases on mRNA.

Question 24

What are the 3 types of codons?

Answer 24

Start codon, amino acids and stop codons.