Biology lecture final exam Flashcards
what does Release Factor do?
ends translation by recognizing a stop codon in an mRNA sequence
how do tRNAs participate with amino acids and ribosomes to assemble protein chains?
carry amino acids to the ribosome and join with their complementary codons
how is eukaryotic pre-mRNA processed before it becomes mature mRNA?
RNA splicing
Exons
which are parts of the protein-coding sequence in mRNA
introns
The non-coding regions within the gene on a mRNA
Prokaryotic mRNA
molecule that carries genetic information from DNA to proteins
Eukaryotic mRNA
a molecule that carries genetic information from DNA to ribosomes, which translate it into proteins
how do codons specify the production of a protein/polypeptide chain?
by dictating the order of amino acids to be added to the growing chain, with each codon corresponding to a specific amino acid
Transcription
DNA —> RNA
Translation
RNA —> Protien
how is RNA different from DNA with regards to structure?
DNA is typically double-stranded, forming a double helix, while RNA is usually single-stranded
how is RNA different from DNA with regards to synthesis?
RNA is not self-replicating like DNA
how is RNA different from DNA with regards to function?
DNA primarily functions the storage of genetic information
RNA carrying the genetic code from DNA to ribosomes where it is translated into proteins
how do transcription factors work to stimulate the rate of transcription?
binding to specific DNA sequences and either promoting or inhibiting the process
Transcription factors
proteins that regulate transcription
what is the function of promoter?
acts as a binding site for RNA polymerase
what is the function of TATA Box?
define the direction of transcription and also indicates the DNA strand to be read
what is the function of enhancer?
acts as a regulatory element to significantly increase the transcription of a nearby gene
what is the function of silencer?
regulatory element to suppress the transcription of a nearby gene
how does Lac Repressor inhibit transcription of Lac Operon ?
by binding to a specific DNA sequence called the “operator” which is located near the promoter region of the operon, physically blocking RNA polymerase from accessing the promoter and initiating transcription when lactose is not present
Lac Repressor
a protein that controls the transcription of genes in bacteria that metabolize lactose
Lac Operon
a set of genes in bacteria that control the uptake and metabolism of lactose
promoter
The nucleotide sequence in DNA to which RNA polymerase attaches to begin transcription
operon
a group of genes that are transcribed together to create a single (mRNA) molecule that encodes multiple proteins
inducible gene
gene that is only expressed when a specific substance, called an “inducer”, is present in the environment
structural gene
a gene that codes for a protein directly involved in the structure or function of an organism
constitutive gene
A gene that is constantly transcribed
operator
the DNA segment where the repressor molecule binds to the operon model And stops Rna polymerase
inducer
a molecule called an inducer can bind to the repressor, inactivating it
describe the DNA and protein components that make a transcription repressor system possible
specific DNA sequence called an “operator” located near the gene’s promoter, where a repressor protein binds to physically block RNA polymerase from accessing the promoter, thereby preventing transcription of the gene
How is restriction enzymes related to palindrome?
“recognition sites” which are often palindromic
how are restriction enzymes and DNA Ligase used in gene splicing?
restriction enzymes are used to “cut” DNA at specific sequences, creating fragments with complementary ends (sticky ends), while DNA ligase acts as a “glue” to join these DNA fragments together, essentially splicing them to form a new recombinant DNA molecule
how are plasmids used in gene splicing and formation of recombinant DNA?
scientists use plasmids as vectors in gene splicing and recombinant DNA technology by inserting desired genes into the plasmid, allowing for the replication
what is the purpose of PCR?
To produce multiple copies of DNA
how do primers determine which region of DNA to amplify?
by binding to complementary sequences on the DNA template
what are “primers”
a short, single-stranded DNA sequence that acts as a starting point for DNA synthesis
what happens to template DNA and DNA primers at different
temperatures?
At high temperatures, template DNA and DNA primers will separate into single strands due to the disruption of hydrogen bonds between base pairs, a process called denaturation
at lower temperatures, they can re-anneal and bind to each other if the sequence is complementary
how many copies of DNA are produced during each cycle of PCR?
two copies
what are “dideoxy nucleotides”
modified nucleotides that are used to terminate DNA chains during DNA sequencing
how are dideoxy nucleotides used in Sanger
sequencing?
to terminate DNA chain elongation
what is the original function of CRISPR in bacteria?
to act as a defense mechanism against invading viruses
what is the function of Cas9 enzyme?
acts as a “molecular scissor” that cuts DNA at a specific location, allowing for targeted gene editing within the genome
what are VNTRs (variable numbers of tandem repeats)
sections of DNA where a short sequence of nucleotides is repeated multiple times in a row
what are STRs (short tandem repeats)
DNA sequences that are made up of short repeating units, typically 2–6 base pairs long
VNTRs and STRs are used to distinguish people from one another….
by analyzing the varying number of times specific short DNA sequences repeat at certain locations on their genome
how do STRs detected and visualized?
Polymerase chain reaction (PCR) and gel electrophoresis
Restriction enzymes
proteins that cut DNA at specific sequences
Gene splicing
altering an organism’s DNA by cutting and inserting genes, or by modifying pre-mRNA to produce different proteins
what are plasmids?
a small circular DNA molecule found in bacteria and some other microscopic organisms
What is the definition of biological evolution?
the process by which the inherited traits of organisms change over generations
How have canines and Brassicas evolved?
Canines from wolves and mustard seed
How does the fossil record provide evidence of evolution?
showcasing a progression of life forms over time, demonstrating that organisms from the past were different from those present today, and by revealing transitional fossils that show the evolutionary links between different species
How is whale evolution illustrated by the changing skeletal structures of “missing
links” and current whales?
Why is archaeopteryx considered a “missing link”
its fossil exhibits characteristics of both birds and reptiles
how did DNA confirm the
link between dinos and ducks
How do DNA and protein sequences indicate evolutionary relationships?
by showing the similarities and differences between organisms’ genetic codes
How do DNA errors indicate evolution has occurred, as illustrated by the
GULO gene?
they show a loss of functionality in a gene that is present and functional in related species
How do protein sequence changes indicate evolution, as illustrated byCytochrome C?
showing how the amino acid sequence of a protein varies between different species, with more similar sequences signifying closer evolutionary relationships
amylase gene cluster
a region of DNA on a chromosome that contains genes for amylase, an enzyme that breaks down starch into sugars
T cell CCR5 receptor
protein found on the surface of T cells that acts as a key receptor for certain chemokines
lactose metabolism
the process of breaking down lactose into its component sugars, glucose and galactose, which the body then uses for energy
palindrome
sequence that reads the same backward as forward
