GENETICS

What is the function of DNA?

Stores genetic information and instructions for making proteins.

Where is DNA found in a cell?

In the nucleus.

What is a gene?

A segment of DNA that codes for a specific protein/trait.

What are chromosomes made of?

DNA and proteins; humans have 46 chromosomes (23 pairs).

What are the 4 bases of DNA and how do they pair?

A pairs with T, C pairs with G.

What is the base pairing rule in RNA?

A pairs with U, C pairs with G.

What’s the difference between DNA and RNA?

DNA: double-stranded, deoxyribose, thymine. RNA: single-stranded, ribose, uracil.

What is protein synthesis?

The process of making proteins from DNA instructions using RNA.

What are the two steps of protein synthesis?

Transcription (DNA to mRNA), Translation (mRNA to protein at ribosome).

What determines a protein’s function?

Its shape, based on the amino acid sequence.

What is a mutation?

A change in the DNA sequence.

What are three types of gene mutations?

Substitution, insertion, deletion.

Can mutations be inherited?

Yes, if they occur in gametes (sex cells).

What is a genotype?

An organism’s genetic makeup (e.g., AA, Aa, aa).

What is a phenotype?

The physical trait shown (e.g., brown eyes).

What does dominant mean?

An allele that is always expressed if present (A).

What does recessive mean?

An allele only expressed if both are recessive (a).

What is homozygous?

Two of the same alleles (AA or aa).

What is heterozygous?

Two different alleles (Aa).

What does a Punnett square show?

Possible genetic combinations and trait probabilities.

What’s the expected ratio for a Aa x Aa cross?

Genotype: 1 AA : 2 Aa : 1 aa; Phenotype: 3 dominant : 1 recessive.

What is selective breeding?

Choosing parents with desired traits to breed.

What is cloning?

Making a genetically identical organism.

What is genetic engineering?

Inserting genes from one species into another.

What is gel electrophoresis used for?

Separating DNA fragments by size.

Which DNA pieces move farther in gel electrophoresis?

Smaller fragments.

What is gel electrophoresis used for? (another use)

Crime scenes, paternity, comparing DNA.

How can the environment affect gene expression?

External factors influence how traits appear.

Example of environment affecting gene expression?

Identical twins growing to different heights due to diet.