Chapter 14 vocab

How can ionizing radiation alter DNA structure?

- Base Deletion - Breaks in one or both DNA Strands

The stages of cancer progression is?

- Benign growth - Malignant growth - Metastasis

What are the two main types of proteins that are responsible for advancing a cell through the phases of a cell cycle?

- Cyclin-dependent kinases - Cyclins

What causes spontaneous mutations?

- Free radicals produced during metabolic processes that change nucleotide structure. - Insertions of a transposon into a gene. - errors made by DNA polymerase during replication.

What two mechanisms enable a retrovirus to promote cancer?

- It may carry an oncogene in its genome. - It may insert their DNA near proto-oncogenes.

The two main functions of tumor suppressor genes are?

- Maintenance of genome integrity - Negative regulation of cell division

What is true about nucleotide excision repair (NER)?

- The undamaged strand is used as a template to synthesize a normal strand. - A region of several nucleotides in the damaged strand is removed from the sequence.

Which of the following are examples of ionizing radiation?

- X-Rays - Gamma rays

tumor suppressor genes

- p53 - Rb

Chemical mutagens?

-Ethyl methansulfonate -nitrous acid -Nitrogen mustard -Benzopyrene

What are the steps in a growth factor signaling pathway that promote cell division? Write in the correct order.

1. A growth factor binds to a receptor and activates it. 2. An intracellular signal transduction pathway is activated. 3. Transcription factors in the nucleus are activated 4. Genes that promote cell division are transcribed

What are the events in order, of what occurs in the progression of lung cancer in the correct order, beggining with the first event at the top?

1. Hyperplasia 2. Loss of cilliated cells 3. Dysplasia 4. Metastasis

What genetic changes can convert a proto-oncogene into an oncogene?

1. Missense mutations 2. Gene amplifications 3. Chromosomal translocations 4. Retroviral insertions

What mutations in order from least effect on polypeptide sequence at the

1. Silent 2. Missense 3. Nonsense

The events that occur in nucleotide excision repair in E.coli in the correct order?

1. The UvrA-UvrB complex identifies a damaged site 2. UVrC makes cuts on both sides of the damaged site 3. UvrD binds and removes the damaged region. 4. DNA polymerase synthesizes new DNA to fill the gap 5. DNA ligase seals the newly synthesized DNA to the original strand.

methyl-directed mismatch repair

A base pair mismatch is detected. A portion of the DNA strand containing the mismatch is removed and then replaced with new DNA.

What is a proto-onccogene?

A normal gene that can become an oncogene if it is mutated?

What is a mutagen?

A physical or chemical agent that causes mutations.

Promoter

A possible increase or decrease in the rate of transcription

Direct Repair

A repair enzyme recognizes an incorrect structure. The incorrect structure is converted back to a correct structure.

A missense mutation may not affect protein structure and function if the altered amino acid has what?

A similar side chain

Dysplasia

Abnormal cell morphology

The p53 protein can arrest the cell cycle at the G1 stage by?

Activating genes that encode proteins that stop the cell cycle

5-bromouracil

Acts as a base analouge

Chemical mutagens can alter DNA structure by causing?

Alkylation of bases, deamination of bases

What are somatic cells?

All cells of the body that are not germ line cells.

Nitrogen mustard

Alylates bases

What test is used to evaluate the ability of substance to cause mutations?

Ames Test

Base excision and nucleotide excision repair

An abnormal base or nucleotide is recognized, and a portion of the strand containing the damaged strand is removed and replaced with new DNA.

A tumor is?

An overgrowth of cells

In response to severe DNA damage that is too extensive to be repaired, the p53 protein will activate other genes that promote (blank)?

Apoptosis

In most cases, how many genetic changes in a cell lineage typically occur before cancer develops?

At least 10

In order for cancer cells to from a lung carcinoma to metastasize, they must penetrate the Blank membrane, which is a sheetlike layer of extracellular matrix that provides a barrier between the lung cells and the bloodstream.

Basement

How can gene amplification of a proto-oncogene cause cancer?

By generating too much of the encoded protein

The disease of multicellular organisms that is characterized by uncontrolled cell division is known as?

Cancer

Agents that increase the likelihood of developing cancer are known as?

Carcinogens

What proteins monitor the integrity of the genome and prevent a cell from progressing through a certain point in the cell cycle?

Checkpoint proteins

In the Ames test, you expose S. typhimurium cells that cannot synthesize histidine to compound X, then plate them on a medium lacking histidine. The next day you observe a higher number of colonies on the plate versus the control plate, which has bacteria with no exposure. What reasonable conclusion can you draw?

Compound x is a mutagen

The p53 protein is encoded by a tumor-supressor gene which is expressed when what is damaged?

DNA

Seals newly synthesized DNA to the original strand?

DNA ligase

Synthesizes new DNA to fill in the gap?

DNA polymerase

Nitrous acid (chemical mutagen)

Deanimates base

A silent mutation results in a polypeptide with an unchanged amino acid sequence because the genetic code is?

Degenerate

Which type of DNA repair involves an enzyme that recognizes an incorrect structure in a base and restores the base to its original structure?

Direct Repair

Cancer usually requires one or two genetic changes to the same cell lineage? True or false?

False, cancer usually requires around 10 or more genetic changes to the same cell lineage.

Which phases of the cell cycle are the three checkpoints located?

G1, G2 and metaphase

What is a genetic event in which the number of copies of a gene is increased?

Gene amplification

Gametes are produced by?

Germ line cells

The activity of an oncogene is?

Higher than that of the normal gene

The Rb protein blocks cell division by

Inhibiting the E2F transcription factor

Benzo(alpha)pyrene

Inserts between bases of the double helix, causing additions and deletions.

X-rays and gamma rays are examples of what type of radiation, that is a type of electromagnetic radiation that can create free radicals.

Ionizing radiation

What is the function of the Rb protein?

It inhibits cell division.

Which of the following best describes the retinoblastoma (Rb) gene?

It is a tumor -suppressor gene involved in the negative regulation of cell division.

The process by which cancerous cells spread through the body via the bloodstream or surrounding body fluids is termed?

Metastasis

The expression of a tumor-suppressor gene may be reduced when CpG near its promoter region are?

Methylated

A specific type of point mutation called is a base substitution that changes a single amino acid in a polypeptide sequence?

Missense

What type of mutation changes a single amino acid in a polypeptide sequence?

Missense

A normal proto-oncogene may become an oncogene if it is?

Mutated, amplified and translocated to a different chromosome

Cancer usually affects older people because they are likely to have more?

Mutations

What mutation involves a change from a normal codon to a stop codon?

Nonsense

Intergenic region

Not as likely to have an effect on gene expression.

Consider a normal gene that is needed for growth, If this gene becomes overactive, it may contribute to cancer. It then becomes a?

Oncogene

Over the past four decades, researchers have identified many types of? Examples include growth factor receptors, transcription factors, and intracellular signaling proteins.

Oncogenes

What exhibits nucleotide excision repair?

Plants, Bacteria, Mice, Humans

Splice junctions

Possible change in the ability of pre mRNA to be properly produced

Translational regulatory element

Possible change in the ability of protein to be produced from mRNA

Apoptosis is a term that refers to?

Programmed cell death

Bacterial colonies can be transferred from a master plate to secondary plate in the same configuration using a transferring agent such as a sterile velvet cloth. This is?

Replica plating

base substitution - Silent

Silent causes no change

Sperm and egg cells are termed germ line cells. In contrast, cells of the skin, muscle, heart, and liver are examples of (Blank) cells.

Somatic

Animal cells are classified into two main types. Which ones?

Somatic cells and germ line cells

Silent mutations have no effect on the amino acid sequence of a polypeptide because:

The base substitution results in a codon that specifies the same amino acid as the original sequence.

In nucleotide excision repair, what serves as the template for synthesis of new DNA to replace the damaged strand?

The complementary strand of DNA

Metastasis

The spread of cancer cells through the bloodstream

Hyperplasia

Thickening of the epithelium

When the addition or deletion of nucleo tides does not occur in a multiple of ______ nucleotides, the result is a frameshift mutation?

Three

When the addition or deletion of nucleotides does not occur in a multiple of (blank) nucleotides, the result is a frameshift mutation?

Three

Few viruses are known to cause cancer.

True

True or false: All living things possess mechanisms allowing them to minimize mutation?

True

New mutations are much more likely to be harmful than beneficial to the individual. True or false?

True!

Elimination of the function of a blank gene promotes cancer?

Tumor supressor

Maintenance of genome integrity and negative regulation of cell division are the two main functions of:

Tumor-suppressor genes

The genes encoding proteins involved in the regulation of normal cell growth and thus the prevention of cancer are called?

Tumor-suppressor genes

Genes that normally function to prevent cancerous growth are called?

Tumor-supressor genes

Cuts DNA on both sides of the damaged site?

UVrC

Identifies a damaged site?

UvrA/UvrB complex

Removes the damaged region?

UvrD

What genetic diseases affect DNA repair systems in humans?

Xeroderma pigmentosum Cockayne syndrome

base subsitution mutation

a mutation that involves the substitution of a single base in the DNA for another base

base substitution - missense

changes one amino acid

base substitution - nonsense

changes to a stop codon

addition of a single base

frameshift - produces a different amino acid sequence

Point mutation

gene mutation in which a single base pair in DNA has been changed

Agents that cause mutations are?

mutagens.

UV light is an example of?

nonionizing radiation

The protein product of what tumor suppressor gene acts to sense DNA damage, promote DNA repair, and halt cell division?

p53