Genetic 10, 11, 12, 13

How can tandem repeat polymorphisms be classified?

Into minisatellites and microsatellites (STRs), depending on the length of the repeat unit

What are large repetitive DNA elements in the genome called?

Satellite DNA

How can repetitive DNA elements be analyzed?

By PCR amplification followed by gel electrophoresis to compare fragment lengths.

What is the difference between minisatellites and microsatellites?

Minisatellites have longer repeat units, while microsatellites have very short repeat units (1–6 bp).

How are microsatellites known in forensic genetics?

STRs (Short Tandem Repeats).

Where are most STRs found in the genome?

Most STRs are found in non-coding regions of the genome

How many base pairs are in the human haploid genome?

Approximately 3.2 billion base pairs.

What are transposons?

Transposons are DNA elements that can move to different positions within the genome.

What is the humoral immune response?

“An immune response mediated by B cells that produce antibodies.”

What is the cell-mediated immune response?

An immune response mediated by T cells that act against infected or abnormal cells

What is the two-hit hypothesis?

“Both alleles of a tumor suppressor gene must usually be inactivated for its function to be lost.”

What are tumor suppressor genes?

Genes that normally prevent uncontrolled cell growth and tumor formation

What is a proto-oncogene?

A normal gene that promotes cell growth and division and can become an oncogene when abnormally activated.

What is an oncogene?

An abnormally activated gene that promotes uncontrolled cell growth and can contribute to cancer.

What activity do oncogenes have?

“Oncogenes promote cell growth and proliferation.”

How can oncogenes arise?

Oncogenes arise through activating changes in proto-oncogenes, such as mutations, gene amplification, or chromosomal translocations

What observation led to the two-hit hypothesis?

Hereditary tumors appeared earlier than sporadic tumors, suggesting that two genetic hits are required.

Why do species that reach sexual maturity later tend to live longer?

Because successful reproduction requires longer survival, natural selection favors traits that increase longevity.

What are serpins?

Serpins are a family of proteins that mainly inhibit serine proteases

What are proteases?

Proteases are enzymes that degrade proteins by breaking peptide bonds

How is DNA organized in bacteria?

Bacterial DNA is usually a circular, double-stranded chromosome located in the nucleoid

Where does DNA replication start in bacteria and how does it proceed?

Replication starts at a single origin called oriC and proceeds bidirectionally with two replication forks

Why can loss-of-function mutations be lethal in bacteria?

Because bacteria are usually haploid, they have no second gene copy to compensate for the loss of an essential gene

What is a loss-of-function mutation?

A mutation that reduces or eliminates the function of a gene

What is a gain-of-function mutation?

A mutation that increases the activity of a gene product or gives it a new function

What would happen if the same genetic information were always passed on and there were too little genetic variation?”

The population has a reduced ability to adapt to environmental changes and may be more vulnerable to diseases.

Why would bacteria be mostly clonal without horizontal gene transfer?

Because bacteria reproduce asexually by binary fission, producing genetically almost identical daughter cells.

Why can bacteria adapt quickly to changing environmental conditions?

Because they reproduce rapidly, have large populations, and gain genetic variation through mutations and horizontal gene transfer

What is parasexuality in bacteria

The exchange of genetic material between bacteria without sexual reproduction

What did the Lederberg and Tatum experiment demonstrate?

It demonstrated that bacteria can exchange genetic information and undergo genetic recombination.