Bio gene expression and cancer Exam

mRNA

Messenger RNA; a molecule that conveys genetic information from DNA to the ribosome, where proteins are synthesized.

Noncoding RNAs

RNA molecules that do not encode proteins but have roles in regulating gene expression.

Operons

Units of genetic expression in prokaryotes, where related genes are controlled together.

Transcription Factors

Proteins that promote the binding of RNA polymerase to DNA in order to initiate transcription.

Epigenetic Inheritance

Transmission of information from one generation to the next that does not involve the nucleotide sequence but involves chemical modifications.

Nuclear Transplantation

A method of cloning where the nucleus of a donor cell is inserted into an egg cell that has had its nucleus removed.

Therapeutic Cloning

Cloning aimed at producing embryonic stem cells for medical purposes.

Proto-oncogene

A normal gene that promotes cell division; mutations can turn it into an oncogene which leads to uncontrolled cell growth.

Tumor-suppressor Genes

Genes that regulate cell division; mutations that inactivate these genes can lead to cancer.

Signal Transduction Pathways

Biological pathways that relay signals from outside the cell to elicit a response within the cell.

mRNA

Messenger RNA; a molecule that conveys genetic information from DNA to the ribosome, where proteins are synthesized.

Noncoding RNAs

RNA molecules that do not encode proteins but have roles in regulating gene expression.

Operons

Units of genetic expression in prokaryotes, where related genes are controlled together.

Transcription Factors

Proteins that promote the binding of RNA polymerase to DNA in order to initiate transcription.

Epigenetic Inheritance

Transmission of information from one generation to the next that does not involve the nucleotide sequence but involves chemical modifications.

Nuclear Transplantation

A method of cloning where the nucleus of a donor cell is inserted into an egg cell that has had its nucleus removed.

DNA

A molecule that carries genetic information, made of two polynucleotide strands forming a double helix.

RNA

A polymer of nucleotides that plays a role in coding, decoding, regulation, and expression of genes.

Polynucleotide

A polymer made up of nucleotide monomers, which form the backbone of DNA and RNA.

DNA polymerase

An enzyme that synthesizes new DNA strands by adding nucleotides to a pre-existing strand.

Transcription

The process of copying a segment of DNA into RNA.

Translation

The process of synthesizing a polypeptide from an mRNA template.

Codon

A sequence of three nucleotides in mRNA that codes for an amino acid.

Mutations

Changes in the genetic information of a cell or virus that can affect gene function.

Lytic cycle

A viral reproductive cycle in which the virus replicates and bursts the host cell.

Lysogenic cycle

A viral reproductive cycle in which the viral DNA integrates into the host chromosome and is replicated with it.

Prion

An infectious protein that can cause neurodegenerative diseases in animals.

Plasmid

A small, circular DNA molecule within a bacterium that can replicate independently of chromosomal DNA.

What are the roles of DNA and RNA in genetics?

DNA contains the genetic blueprint for all living organisms, while RNA is involved in translating that blueprint into proteins and regulating gene expression.

Describe the processes of transcription and translation in protein synthesis.

Transcription is the process of converting DNA into RNA, while translation is the decoding of that RNA into a polypeptide chain, leading to protein formation.

What are the differences between the lytic and lysogenic cycles in viral reproduction?

The lytic cycle results in the immediate replication of the virus and destruction of the host cell, whereas the lysogenic cycle integrates viral DNA into the host's genome, allowing it to replicate silently.

How do mutations affect gene function?

Mutations are changes in the genetic code that can lead to altered protein function, which may result in beneficial, harmful, or neutral effects on the organism.

What is a plasmid and its significance in bacterial genetics?

A plasmid is a small, circular DNA molecule that can replicate independently within a bacterium, often carrying genes that confer advantages such as antibiotic resistance

Gene Expression

The process by which a gene's information is used to synthesize gene products such as proteins.

Operon

A functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter.

Promoter

A region of DNA where RNA polymerase binds to initiate transcription.

Operator

A segment of DNA that a regulatory protein binds to, controlling the transcription of nearby genes.

Lac Operon

An inducible operon in bacteria that contains genes for the digestion of lactose and is activated in the presence of lactose.

Repressor

A regulatory protein that inhibits transcription of a gene.

Repressible Operon

An operon that is normally active and can be turned off by a repressor molecule.

Inducible Operon

An operon that is normally off and can be turned on by the presence of a specific molecule.

Negative Control

A regulatory mechanism that stops transcription when repressor molecules are active.

Positive Control

A regulatory mechanism that increases the rate of transcription.

Eukaryotic Gene Regulation

A complex process that does not utilize operons and involves multiple regulatory mechanisms including transcription factors and epigenetic modifications.

X-inactivation

A process in female mammals where one of the two X chromosomes is randomly inactivated.

Alternative Splicing

A post-transcriptional mechanism that allows a single gene to produce multiple proteins by combining different coding sequences.

miRNA

A small non-coding RNA molecule that regulates gene expression by binding to mRNA and inhibiting its translation.

Post-Translational Control

Regulation that occurs after a protein has been synthesized, including modifications that determine protein functionality.

Histones

Proteins around which DNA is tightly wound to form nucleosomes, playing a key role in gene regulation.

Euchromatin

A form of chromatin that is less densely packed and actively encodes genes.

Heterochromatin

A form of chromatin that is tightly packed and typically does not encode genes.

Griffith's Transformation Principle

The concept that something from the heat-killed smooth strain of bacteria could transform the rough strain into a virulent form.

Bacteriophages

Viruses that infect bacteria, composed of a protein capsule surrounding DNA.

Chargaff's Rules

In any organism, the amount of adenine equals thymine (%A = %T) and the amount of cytosine equals guanine (%C = %G).

Rosalind Franklin

Scientist known for her work with X-ray crystallography that revealed the structure of DNA.

Semiconservative Replication

A type of DNA replication where each new DNA molecule contains one original strand and one newly synthesized strand.

DNA Polymerase

The enzyme that synthesizes new DNA strands by adding complementary nucleotides to a template strand.

Okazaki Fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

Transcription

The process of synthesizing mRNA from a DNA template.

Ribosomes

Cellular structures where protein synthesis occurs; composed of rRNA and proteins.

Point Mutation

A genetic mutation where a single nucleotide base is changed, inserted, or deleted from a sequence.

Missense Mutation

A mutation that results in the substitution of one amino acid for another in a protein.

Nonsense Mutation

A mutation that converts an amino acid codon into a stop codon, prematurely terminating protein synthesis.

Gene Repair

The processes involving proofreading and repair enzymes that maintain the integrity of DNA.

Cancer

A condition when a cell loses control of the cell cycle, leading to uncontrolled growth.

Contact Inhibition

A characteristic of normal cells that prevents them from dividing when there is no space; cancerous cells lack this.

Proto-oncogene

A normal gene that helps control cell division; when mutated, it becomes an oncogene.

Oncogene

A mutated proto-oncogene that causes excessive cell division.

Tumor-suppressor gene

A gene that regulates cell division, and its inactivation can lead to cancer.

Chemotherapy

A treatment for cancer that typically targets fast-growing cells, using drugs like fluorouracil and taxol.

Radiation therapy

A cancer treatment that damages the DNA of cancer cells to induce cell death.

GMO (Genetically Modified Organism)

An organism whose DNA has been altered through genetic engineering techniques.

Gene Therapy

A technique that modifies a person's genes to treat or prevent disease.

PCR (Polymerase Chain Reaction)

A method used to amplify small samples of DNA for analysis.

Gel Electrophoresis

A technique used to separate DNA fragments based on size.

Transgenic

An organism that has been genetically modified to contain a gene from another species.