Chapter 9 - What Genes Are

What is CRISPR used for?

• Genome editing: adding/ deleting genes

• A combination of a protein and RNA

What is xenotransplantation?

The process of transplanting organs from non-human animals into humans.

What is each nucleotide composed of?

• The sugar deoxyribose

• A phosphate group

• One of four bases (Adenine, Cytosine, Guanine, Thymine)

What is a base pair?

Two nucleotides held together by hydrogen bonds between their bases.

What are the base pairing rules?

• Adenine can only pair with Thymine

• Cytosine can only pair with Guanine

What does complementary base-pairing do?

Allows original strands to serve as “template strands” on which new strands can be built through complementary base-pairing.

What is a double helix?

DNA ladder twists into a spiral

What does CRISPR stand for?

clustered regularly interspaced short palindromic repeats

What are nucleosomes?

“Beads” made from short lengths of double-stranded DNA wound around histone proteins.

What is DNA replication?

The duplication of a DNA molecule

• Occurs before a cell enters mitosis

How many steps does DNA replication take?

Three

What is semiconservative replication?

Each new DNA double helix contains one old (template) strand and one new strand.

What is polymerase chain reaction (PCR)

• A technique that can produce millions of copies of a DNA sequence in less than an hour.

• Relies on heat

• Uses targeted primers to start the replication process.

What is a mutation?

A change to the sequence of nucleotides in an organism’s DNA.

What is a point mutation?

The change of one nucleotide in a single base pair.

What is a chromosomal abnormality?

The addition or deletion of one or more whole chromosomes.

What is subsitution?

One nucleotide is substituted for another in the DNA sequence of the gene.

What is insertion?

One nucleotide is inserted into a DNA sequence.

What is deletion?

One nucleotide is deleted from a DNA sequence.