Chapter 14 BIOS

How many chromosomes do humans have?

• 22

• 23

• 24

• 46

Answer explanation

Humans have 23 pairs of chromosomes, totaling 46 chromosomes. Therefore, the correct answer is 23.

Approximately how many base pairs are there in the human genome?

• 3 million

• 30 million

• 300 million

• 3 billion

Answer explanation

The correct answer is 3 billion because the human genome consists of approximately 3 billion base pairs.

How many genes are encoded in the human genome?

• 2,000 – 2,500 genes

• 20,000 – 25,000 genes

• 200,000 – 250,000 genes

• 2,000,000 – 2,500,000 genes

Answer explanation

The correct answer is 20,000 – 25,000 genes as this range represents the estimated number of genes encoded in the human genome.

What is a gene?

• A protein that encodes for DNA

• A DNA sequence encoding a functional molecule

• A type of chromosome

• A pair of amino acids

Answer explanation

A gene is a DNA sequence encoding a functional molecule, making the correct answer choice 'A DNA sequence encoding a functional molecule'.

Which of the following is a correct base pair in DNA?

• A=C

• C=T

• G=A

• A=T

Answer explanation

The correct base pair in DNA consists of Adenine (A) pairing with Thymine (T), making the choice A=T the correct answer.

What did biochemists realize about chromosomes after isolating the nucleus?

• Chromosomes were made of only protein

• Chromosomes were made of DNA + protein

• Chromosomes were made of only DNA

• Chromosomes were not related to DNA or protein

Answer explanation

Biochemists realized that chromosomes were made of DNA + protein after isolating the nucleus.

What was determined to be the molecule that holds genetic information?

• RNA

• Protein

• DNA

• Lipids

Answer explanation

DNA was determined to be the molecule that holds genetic information, making it the correct choice.

What was the role of protein in chromosomes as determined by labeling experiments and transformation experiments?

• Protein held the genetic information

• Protein was the structural component

• Protein was not part of chromosomes

• Protein was the energy source for chromosomes

Answer explanation

Protein was the structural component of chromosomes as determined by labeling experiments and transformation experiments.

What is DNA made up of?

• Amino acids

• Nucleotides

• Proteins

• Lipids

Answer explanation

DNA is made up of nucleotides, which are the building blocks of DNA molecules. Nucleotides consist of a sugar, a phosphate group, and a nitrogenous base.

How many possible nitrogenous bases are there in DNA?

• 2

• 4

• 6

• 8

Answer explanation

There are 4 possible nitrogenous bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair up to form the genetic code.