exam 4 bio

Chapter 14 – DNA: The Genetic Material

Flashcard 1
Q: What did Griffith's experiment demonstrate?
A: That genetic material can be transferred between bacteria through transformation.

Flashcard 2
Q: What conclusion did Avery, MacLeod, and McCarty draw from their experiments?
A: DNA is the transforming material responsible for heredity.

Flashcard 3
Q: What was shown by Hershey and Chase’s experiment?
A: DNA, not protein, is the genetic material injected by viruses into bacteria.

Flashcard 4
Q: What are the three components of a DNA nucleotide?
A: A phosphate group, deoxyribose sugar, and a nitrogenous base.

Flashcard 5
Q: What is the difference between purines and pyrimidines?
A: Purines (A, G) have two rings; pyrimidines (C, T) have one ring.

Flashcard 6
Q: How do DNA and RNA nucleotides differ?
A: RNA has ribose instead of deoxyribose and uracil instead of thymine.

Flashcard 7
Q: What bond connects nucleotides in a DNA strand?
A: Phosphodiester bonds between the phosphate of one and the 3’ OH of another.

Flashcard 8
Q: What bonds hold the two strands of DNA together?
A: Hydrogen bonds between complementary bases.

Flashcard 9
Q: What does Chargaff’s rule state?
A: A = T and G = C in any DNA molecule.

Flashcard 10
Q: What did Rosalind Franklin’s X-ray crystallography reveal?
A: DNA is a helical structure with a consistent diameter.

Flashcard 11
Q: What is the Watson and Crick model of DNA?
A: A double helix with antiparallel strands and complementary base pairing.

Flashcard 12
Q: What does "antiparallel" mean in DNA structure?
A: The two strands run in opposite 5' to 3' directions.

Flashcard 13
Q: What is semiconservative replication?
A: Each new DNA molecule consists of one old and one new strand.

Flashcard 14
Q: What is semidiscontinuous replication?
A: Leading strand is synthesized continuously; lagging strand in Okazaki fragments.

Flashcard 15
Q: What does DNA polymerase require to begin synthesis?
A: An RNA primer.

Flashcard 16
Q: What enzymes are involved in DNA replication?
A: DNA polymerase, primase, DNA ligase, DNA gyrase, helicase.

Chapter 15 – Genes and How They Work

Flashcard 17
Q: What are the three main types of RNA?
A: mRNA (messenger), rRNA (ribosomal), tRNA (transfer).

Flashcard 18
Q: What is the relationship between genes and chromosomes?
A: Genes are segments of DNA located on chromosomes.

Flashcard 19
Q: What is a gene?
A: A DNA sequence that encodes a functional product, usually a protein.

Flashcard 20
Q: What are the structural parts of a gene?
A: Promoter, regulatory sequences, start site, introns, exons, termination sequence.

Flashcard 21
Q: What is the genetic code?
A: A set of triplet codons in DNA or mRNA that specify amino acids.

Flashcard 22
Q: What is transcription?
A: The process of synthesizing RNA from a DNA template.

Flashcard 23
Q: What are the end products of transcription?
A: A strand of RNA (usually mRNA in protein-coding genes).

Flashcard 24
Q: How do you transcribe DNA to mRNA?
A: Replace A with U, T with A, C with G, and G with C.

Flashcard 25
Q: What modifications occur to eukaryotic pre-mRNA?
A: Addition of 5’ cap, 3’ poly-A tail, and splicing of introns.

Flashcard 26
Q: What does tRNA do?
A: Carries amino acids to the ribosome during translation.

Flashcard 27
Q: What is the role of ribosomes?
A: Facilitate decoding mRNA and forming peptide bonds during translation.

Flashcard 28
Q: What is the genetic code chart used for?
A: Translating mRNA codons into amino acids.

Flashcard 29
Q: What is translation?
A: The process of synthesizing proteins using mRNA as a template.

Flashcard 30
Q: What is protein synthesis?
A: The entire process from DNA transcription to protein translation.

Flashcard 31
Q: How are transcription and translation related?
A: Transcription creates mRNA, which is translated into a protein.

Flashcard 32
Q: How does prokaryotic protein synthesis differ from eukaryotic?
A: Prokaryotes couple transcription and translation; eukaryotes separate them and process mRNA.

Flashcard 33
Q: What is the role of splicing in protein diversity?
A: Splicing can produce multiple proteins from one gene by removing different introns.

Chapter 16 – Control of Gene Expression

Flashcard 1
Q: Why is gene control necessary for a cell's survival?
A: It allows cells to respond to environmental changes and maintain homeostasis.

Flashcard 2
Q: How do regulatory proteins control gene expression?
A: They bind to DNA and either block or promote RNA polymerase binding to promoters.

Flashcard 3
Q: What is transcriptional control?
A: Regulation of whether and how much a gene is transcribed into RNA.

Flashcard 4
Q: What is post-transcriptional control?
A: Regulation after RNA is made, affecting RNA stability, translation, or processing.

Flashcard 5
Q: What is an inducible operon?
A: An operon activated by the presence of a substrate (e.g., lac operon with lactose).

Flashcard 6
Q: What is a repressible operon?
A: An operon turned off by the presence of a product (e.g., trp operon with tryptophan).

Flashcard 7
Q: In the lac operon, what happens when lactose is absent?
A: The lac repressor binds to the operator, blocking transcription.

Flashcard 8
Q: In the lac operon, what happens when lactose is present?
A: Lactose (allolactose) binds the repressor, causing it to release from the operator, allowing transcription.

Flashcard 9
Q: What is glucose repression?
A: Cells preferentially use glucose by inhibiting the use of other sugars like lactose.

Flashcard 10
Q: What is the role of CAP (catabolite activator protein)?
A: CAP activates transcription when glucose is low by binding with cAMP.

Flashcard 11
Q: How do eukaryotic gene regulation and prokaryotic gene regulation differ?
A: Transcription and translation occur at the same location in eukaryotes, but at different locations in prokaryotes

Flashcard 12
Q: What are general transcription factors?
A: Proteins necessary to form the basic transcription initiation complex at all promoters recognized by RNA polymerase II.

Flashcard 13
Q: What are specific transcription factors?
A: Proteins that regulate transcription in a tissue-specific or time-specific manner by enhancing or repressing expression.

Flashcard 14
Q: What is a transcription complex?
A: A large assembly of proteins including general and specific transcription factors that regulate transcription.

Flashcard 15
Q: How does chromatin structure affect gene expression?
A: DNA wrapped around histones can restrict access; chromatin must be remodeled for transcription to occur.

Flashcard 16
Q: How can translation initiation be regulated?
A: By translation repressor proteins that block ribosome binding to mRNA.

Flashcard 17
Q: How does mRNA stability influence gene expression?
A: mRNAs with short half-lives are degraded faster, reducing protein production.

Chapter 17 – Biotechnology

Flashcard 1
Q: Why are plasmids and viruses important in genetic engineering?
A: They are used as vectors to carry foreign DNA into host cells.

Flashcard 2
Q: What is the natural function of restriction endonucleases?
A: They cut foreign DNA to protect bacteria from viruses.

Flashcard 3
Q: How do bacterial cells protect their own DNA from restriction enzymes?
A: By methylating their DNA at the recognition sites.

Flashcard 4
Q: What are "sticky ends" and why are they important?
A: Sticky ends are single-stranded overhangs created by restriction enzymes, allowing easy joining of DNA fragments.

Flashcard 5
Q: What are the four steps of genetic engineering (gene cloning)?
A: 1. Cut DNA with restriction enzymes, 2. Insert into a vector, 3. Introduce into host cell, 4. Screen for clones.

Flashcard 6
Q: How are blue-white screens used to identify recombinant clones?
A: White colonies contain the desired insert; blue colonies do not.

Flashcard 7
Q: What is PCR (polymerase chain reaction) used for?
A: Amplifying specific DNA sequences rapidly.

Flashcard 8
Q: What are the three basic steps in a PCR cycle?
A: Denaturation, annealing, and extension.

Flashcard 9
Q: What enzyme is crucial for PCR and why?
A: Taq polymerase, because it is heat-resistant.

Flashcard 10
Q: What does gel electrophoresis do?
A: Separates DNA fragments based on size.

Flashcard 11
Q: What is a DNA library?
A: A collection of cloned DNA fragments stored for research.

Flashcard 12
Q: What are STRs and how are they used?
A: Short tandem repeats; used for DNA fingerprinting.

Flashcard 13
Q: What is the Ti plasmid and how is it used?
A: A plasmid from Agrobacterium used to genetically engineer plants.

Flashcard 14
Q: What are biofuels and how are microalgae involved?
A: Renewable fuels from biomass; microalgae are cultivated to produce lipids for biofuels.

Flashcard 15
Q: How is insulin produced using biotechnology?
A: Human insulin genes are inserted into E. coli to produce insulin.

Flashcard 16
Q: What is FISH (Fluorescent In Situ Hybridization)?
A: A technique to detect specific DNA sequences using fluorescent probes.

Flashcard 17
Q: How do new vaccine technologies differ from traditional ones?
A: They use nucleic acid (DNA or mRNA) or viral vectors instead of weakened viruses.

Flashcard 18
Q: What are stem cells and why are they important?
A: Pluripotent cells that can differentiate into any cell type; used for tissue repair.

Flashcard 19
Q: What is glyphosate resistance in crops?
A: Genetic modification making crops resistant to the herbicide glyphosate.

Flashcard 20
Q: What are Bt crops?
A: Crops engineered to produce Bt toxin, making them resistant to insect pests.

Flashcard 21
Q: What is "stacked" crop technology?
A: Crops engineered with multiple traits, like herbicide and pest resistance.

Flashcard 22
Q: What is Golden Rice and why is it important?
A: Genetically modified rice that produces beta-carotene to prevent vitamin A deficiency.