BIO 130 Test 2 Flashcards
What is the process where homologous chromosomes pair up during prophase 1 of meiosis
Synapsis
Genetic process that occurs during meiosis when homologous chromosomes exchange genetic material
Crossing Over
A process that restructures part of a genome by exchanging genetic material between DNA molecules
Recombination
A breeding experiment that involved reversing the sexes of parents in a cross to determine the role of parental sex in inheritance
Reciprocal cross
Parental Generation, 1st generation, 2nd generation
P, F1, F2
A genetic theory that explains how phenotypic traits are passed down through generations
Particulate Inheritance
Pairs of alleles, or genes are separated into reproductive cells during meiosis
Principle of segregation
trait or gene that is most influential
Dominant
Trait or gene that is less strong, only shows through if it is homozygous
Recessive
two or more traits are fully expressed and neither is dominant or recessive
Codominant
A genetic phenomenon where a heterozygote phenotype is more extreme than either of its parents phenotypes
Overdominant
Different genes and their corresponding trait are separated independently during the development of reproductive cells
Principles of Independent assortment
A characteristic that is determine by genes located on the sex chromosome
Sex-linked trait
A genetic phenomenon where a single DNA variant, or gene, affects multiple traits that may seem unrelated.
Pleiotropy
A genetic phenomenon where the expression of one gene is modified by the expression of one or more other genes.
Epistasis
What are the three purposes of mitosis we discussed in class?
Growth, repair, and asexual reproduction
Why is it important to have regulation checkpoints in the cell cycle?
They act at control mechanisms to make sure the cell is fully grown and ready to divide into two cells
What is the evolutionary explanation for sexual reproduction?
Provides genetic diversity within a population
In what two ways does meiosis increase genetic variation?
Crossing over and Independent Assortment
What are the characteristics of a good model organism for genetic studies?
-a large natural population with a wide range of genetic variations
-a short generation time allowing for rapid observations of new mutations
-easily identifiable phenotypic traits linked to genetic variations
-well established genetic tools for manipulating and analyzing the genome
-a species with a high level of genetic diversity that is also convenient to study in a laboratory setting
Explain Mendel’s model of particulate inheritance
Genetic traits are passed from parent to offspring as discrete units called “particles” meaning that traits are not blended together but inherited as distinct entities
Cell cycle and phases
A series of events that a cell goes through to divide into two new daughter cells
-G1
-S
-G2
-Interphase
-Prophase
-Metaphase
-Anaphase
-Telophase
-Cytokinesis
Mitosis
A process where a single cell divides into two genetically identical daughter cells
Meiosis
A type of cell division that occurs in sexually reproducing organisms to produce gametes, or sex cells like eggs and sperm
Chromsome
The “X” structure carrying DNA
Sister Chromatids
The chromatids that have paired together
Homologous chromosomes
The “XX” structure where one comes from mom and one comes from dad
Ploidy
The number of copies of chromosomes found in each nucleus in a given organism
Autosome
Any chromosome that is a sex chromosome
Transformation
the process where a cell takes up and incorporates foreign genetic material from its surroundings
Semiconservative Replication
the process by which DNA is copied in cells to create two new double-stranded DNA molecules, each with one original strand and one new strand
DNA Polymerase
Replicates DNA
Leading Strand
The strand of nascent DNA which is synthesized in the same direction as the growing replication fork
Lagging Strand
One of two strands of DNA that are found at the replication fork, or junction, in the double helix
mRNA
Messenger RNA is a single stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein
5’ CAP
Protects the mRNA, helps export out of cell, and promotes translation
Poly-A-Tail
Makes the mRNA molecule more stable and prevents its degration
Introns
the segment of DNA that does not code for proteins, gets spliced out
Exons
the segment of DNA that codes for the protein, turns into the mature RNA strand
Splicesomes
large ribonucleoprotein complexes that remove introns from pre-mRNA to create a translatable molecule
RNA polymerase
An enzyme that functions by copying a DNA sequence into an RNA sequence
Template strand
the strand of DNA that serves as the pattern for building a complementary RNA molecule during the process of transcription
Promotor
A DNA sequence that marks the beginning of a gene’s transcription
Terminator
a sequence of nucleotides that marks the end of a gene or operon during transcription
Transcription Factors
A protein that binds to specific DNA sequences on a gene to regulate the rate at which that gene is transcribed into RNA
Ribosomes
a complex molecular machine found within cells, responsible for protein synthesis by translating the genetic code carried by messenger RNA into a chain of amino acids, which then fold to form proteins
Ribozyme
a ribonucleic acid molecule that can catalyze chemical reactions, similar to an enzyme
rRNA
a fundamental component of ribosomes, which are molecular machines that translate genetic information into proteins
Codon
a sequence of three DNA or RNA nucleotides that correspond with a specific amino acid or stop signal during protein synthesis
Anticodon
a sequence of three nucleotides in transfer RNA that matches a specific codon in messenger RNA during protein synthesis
Reading Frame
the specific way a sequence of nucleotides in DNA or RNA is divided into groups of three, called codons, which re then translated into amino acids during protein synthesis
tRNA
transfer RNA is a small RNA molecule that helps translate messenger RNA into proteins
aminoacyl-tRNA-synthase
an enzyme that attaches amino acids to transfer RNAs in order to create aminocylated tRNAs
Wobble
a non standard base pairing in RNA molecules that occur frequently in tRNA’s
Post-Translational Modification
a chemical change that occurs to a protein after it has been translated by a ribosome
Mutation
a change in the DNA sequence of an organism
Mutagen
a physical or chemical agent that can cause permanent changes in an organism’s genetic material(DNA), leading to an increased frequency of mutations above the natural background level
Point Mutation
a genetic change where a single nucleotide base pair in a DNA sequence is altered, either by substitution, insertion, or deletion, resulting in a potential change to the protein produced by a gene
Missense Mutation
A genetic change where a base pair substitution in DNA results in a different amino acid being coded for at a specific position in the resulting protein
Nonsense Mutation
A genetic mutation that causes a protein to be terminated early, resulting in a shorter or nonfunctional protein
Insertion
the addition of one or more nucleotides into a segment of DNA
Deletion
A type of genetic change that involves he absence of a segment of DNA
Frameshift Mutation
a genetic mutation where a deletion or insertion occurs, causing the reading frame to shift, resulting in a different amino acid sequence being produced from that point onwards
Gene Duplication
A process where a section of DNA containing a gene is copied, resulting in the creation of an identical duplicate gene within an organism’s genome
Inversion
a chromosomal rearangment where a segment of a chromosome breaks off and reattaches in the reverse direction
Ribonucleases
enzymes that break down RNA into smaller components
Gene Expression
the process by which the information encoded in a gene is turned into a function
Transcriptional Control
the process by which a cell regulates the conversion of DNA to RNA, which in turn controls gene activity
Translational Control
Governs the efficiency of mRNA’s
Post-Translational Control
the process of regulating proteins after they have been translated
Molecular Chaperones
proteins that help other proteins fold properly, refold after denaturation, and travel to their proper location in the cell
Chromatin
a complex structure made up of DNA tightly wound around protein complexes called histones
Histones
A type of protein found in a chromosome
Enhancer
cis-acting DNA sequences that can increase the transcription of genes
Silencer
Regulatory DNA elements that reduce transcription from their target promoters
Restriction Enzyme
a protein produced by bacteria hat specifically cuts DNA at particular sequences, known as restriction sites
Polymerase Chain Reaction
a laboratory technique that amplifies specific DNA or RNA sequence for analysis.
PCR is used to make many copies of a specific DNA segment from a small sample. This allows researchers to detect and analyze the DNA, which can help diagnose genetic conditions, diseases, and infections.
DNA sequencing
the general laboratory technique for determining the exact sequence of nucleotides, or bases, in a DNA molecule.
dideoxynucleotides
a modified nucleotide that prevents DNA chains from elongating further at a specific point
Open reading frame
a segment of DNA that can be translated into a protein
Central Dogma
a theory that describes the flow of genetic information from DNA to RNA to protein
Sketch and explain the Hershey chase experiment
series of experiments conducted in 1952 by Alfred Hershey and Martha Chase that helped to confirm DNA as the genetic material
Sketch a DNA replication fork and explain the direction of new strand synthesis on each strand
Draw it
Explain semiconservative replication and how the Meselson-Stahl experiment supports it.
Semiconservative replication refers to the process where each new DNA molecule formed during replication contains one strand from the original parent DNA molecule and newly synthesized strand.
The Meselson-Stahl experiment proved that there is mix of olde DNA and new DNA in the double helix.
Explain the Central Dogma using the recipe book analogy
DNA acts like a cookbook, storing all the genetic information needed to make proteins. If the book you photocopied was a cookbook, the protein might be the food you cooked from the recipe.
How does the ribosomes catalyze protein synthesis?
translating the genetic code transcribed in mRNA into an amino acid sequence
What evidence suggests that peptide bonds are catalyzed by a ribosome?
The active site for this reaction, known as the peptide transferase center, is entirely composed of ribosomal RNA within the large ribosomal subunit.
What are the two important features of a tRNA molecule? How is it involved in transcription?
the anticodon loop, which contains a sequence of three nucleotides complementary to a specific mRNA codon, and the amino acid attachment site at the 3’ end, where the corresponding amino acid is attached
What are the common types of post-translational modification?
Phosphorylation, methylation, acetylation
Why are these enzymes in the cell that destroy mRNA?
ribonucleases are present in the cell to allow for controlled regulation of protein synthesis by ensuring that mRNA molecules don’t persist indefinitely
Discuss the reasons that regulations of gene expression is important
it allows organisms to adapt to changing environments, control cell differentiation during development, conserve energy by only expressing necessary genes, and maintain proper cellular function by ensuring the right proteins are produced at the right time in the right amount
Explain how PCR works
It rapidly ceases millions of copies of a specific DNA segment by repeatedly cycling through three steps: denaturation(separating DNA strands), annealing(primer binding), and extension(DNA synthesis), using a special enzyme called DNA polymerase to build new DNA strands based on a template strand, allowing for targeted amplification of a desired DNA region within a sample
Explain how dideoxynucleotides can be used to determine DNA sequence
by acting as chain terminators during DNA replication
Prophase
the first stage of cell division, before metaphase, during which the chromosomes become visible as paired chromatids and the nuclear envelope disappear. The first prophase of meiosis includes the reduction division.
Metaphase
the second stage of cell division, during which the chromosomes become attached to the spindle fibers
Anaphase
the stage in which the chromosomes move away from one another to opposite poles of the spindle
Telophase
the final phase of the cell division, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed
Cytokinesis
the cytoplasmic cell division of the cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells
Interphase
the stage in the cell cycle where a cell grows, replicates its DNA, and prepares for cell division(mitosis) by actively synthesizing proteins and other necessary molecules
Nondisjunction
when chromosomes fail to separate during cell division, resulting in daughter cells with an abnormal number of chromosomes
Genetic Inheritance
the process of passing genetic information, or genes, from parents to their offspring during reproduction
Autosomal Dominant
a pattern of inheritance for genetic traits and disorders were a mutated gene from one parent is enough to cause the condition in a child
Autosomal Recessive
a pattern of inheritance for some genetic disorders and traits
What is an X-linked example and can you draw it?
red-green colorblindness, the disease linked to the X chromosome or the maternal side
Heterozygous
having two different alleles of a particular gene or genes
Homozygous
having two identical versions of a gene, one inherited form each other biological parent
Draw a cross between a heterozygous(Xx) and homozygous(XX)
Draw
Draw a dihybrid cross between XiXi and XIXi
Draw
Epigenome
the collection of chemical compounds that modify DNA and proteins in a cell, which in turn alters gene expression
Methylation
a chemical reaction that adds a methyl group to molecules in the body, such as DNA, proteins, and other molecules. This process can affect how these molecules function.
Acetylation
a chemical reaction that adds an acetyl group to a molecule in place of a hydrogen atom
What is genomic imprinting?
a process that regulates gene expression by silencing one copy of a gene in an individual, depending on whether it came from the mother or the father
Chromatin remodeling
a process that changes the structure of chromatin to make DNA more accessible to transcription factors and the proteins that control gene expression
Transcriptional Control
the process by which a cell regulates the conversion of DNA to RNA, which in turn controls gene activity
Draw DNA replication
Draw
Helicase
an enzyme that separates double-stranded DNA or RNA into single strands
Primers
a short-single stranded DNA sequence that acts as a starting point for DNA synthesis
Ligase
an enzyme that joins two molecules together by forming a new chemical bond
Okazaki Fragments
a short piece of DNA synthesized discontinuously on the lagging strand during DNA replication
DNA Polymerase lll
the primary enzyme responsible for replicating DNA in prokaryotic cells, particularly in bacteria like E. coli
DNA Polymerase l
an enzyme that plays a crucial role in DNA replication, primarily responsible for removing RNA primers from the newly synthesized DNA strand during lagging strand synthesis and filling in the gaps left behind
Topoisomerase
an enzyme which alters the supercoiled form of a DNA molecule
Positive Control
a sample or group that is treated with a known stimulus that should produce a predictable positive result
Negative Control
a group or sample hat does not receive the experimental treatment and is expected to show no change.
Null Hypothesis
the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error
Antibiodies
a blood protein produced in response to and counteracting a specific antigen. Antibodies combine chemically with substances which the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood
Chromatid
one of the two identical halves of a replicated chromosome
