bio module 2 Flashcards
the process of producing offspring that receive genetic material from two parents; it occurs by the production of gametes followed by fertilization to produce a zygote.
sexual reproduction
what are sperm and eggs?
gametes
how are gametes produced?
meiotic cell divsion
a form of cell division that included only one round of DNA replication but two rounds of nuclear division
meiotic cell division
a cross in which female and male parents are interchanged
reciprocal cross
homologous chromosomes fail to separate: All resulting gametes have an extra or missing chromosome
first-division non disjunction
Sister chromatids fail to separate: gametes will have an extra chromosome, missing chromosome or proper number of chromosomes
second-division non disjunction
failure of a pair of chromosomes to separate normally during anaphase of cell division
nondisjunction
interbreeding between two different varieties or species of an organism
hybridization
reductional division, the number of chromosomes are halved from 2n to n
Meiosis 1
equational division in which the number of chromosomes is unchanges
Meiosis 2
the aligned and precise paring of homologous chromosomes in prophase 1 of meiosis
synapsis
A four stranded chromosomal structure characterized by a pair of homologous chromosomes, each consisting of two chromatids, paired side by side held together by one of more chiasmata during prophase 1 of meiosis
bivalent
result from the replication of homologous chromosomes (one is maternal one is paternal), they have the same set of genes in the same order, but are NOT genetically identical
nonsister chromatids
result from the replication of a single chromosome so they are genetically identical
sister chromatids
what is the result of meiotic cell division
daughter cells with half the number of chromosomes as the parents
describes an allele or trait that is only expressed by homozygotes, two BLANK alleles are needed to express the phenotype
recessive
describes an allele or trait that is expressed in heterozygotes; only one BLANK allele is needed to express the phenotype
dominant
the interaction of genes affecting the same trait and it can modify the 9:3:3:1 ratio of phenotypes
epistasis
interaction between genes that modifies the phenotypic expression of genotypes
epistasis
a diagram of family history that summarizes the record of the ancestor- descendant relationships among individuals
pedigree
what is brachydactylyl
a rare dominant trait in which the middle long bone in fingers fail to grow, fingers remain short, this was the first demonstration of dominant mendelian inheritance in humans
what is albinism
a rare recessive trait in which the amount of melanin pigment in the skin, hair and eyes is reduced
mutation in the gene OCA2 leads to
albinism (since this gene encodes a membrane transporter protein thought to be important in the transport of the amino acid tyrosine which is used in the synthesis of the melanin pigement)
the phenomenon in which some individuals with a genotype corresponding to a trait do not show the phenotype, either because of environmental effects of because or interactions with other genes
incomplete penetrance
portion of individuals with a particular genotype that shows the expected phenotype
pentrance
what happens if the penetrance is less than 100%
the trait shows reduced or incomplete penetrance
what is the difference between incomplete penetrance and variable expressivity
incomplete penetrance trait is sometimes expressed and sometimes not
variable expressivity trait is always expressed
the phenomenon in which a particular phenotype is expressed with a degree of severity in different individuals
variable expressivity
what is the difference between a haploid and a diploid
a haploid is made up of one copy of a chromosome (n)
a diploid is made up of two copies of each chromosome (2n)
fusion of haploid cells to produce a diploid cell
fertilization
interpreting pedigrees can be hard due to:
1) incomplete penetrance 2) variable expressivity
genes in the X chromosome
X-linked genes or sex linked genes
the most common allele, genotype or phenotype present in a population; non mutant
wild type
a pattern in which an X chromosome present in a male in one generation is transmitted to a female in the next generation, and in the next generation after that can be transmitted back to make
crisscross inheritance
what is hemophilia
results from a recessive mutation in a gene encoding a protein necessary for blood clotting
organelles in the offspring cells derive from those in the mother
maternal inheritance
what are the types of diversity of inheritance of cytoplasmic organelles?
maternal inheritance, paternal inheritance, biparental inheritance
organelles in the offpsring cells derive from those in the father
paternal inheritance
organelles in the offspring cells derive from those in both parents
biparental inheritance
describes genes that are sufficiently close together in the same chromosome that they do not assort independently
linked genes
progeny in which alleles are present in the same combination as that present in a parent
nonrecombinants
an offspring with a different combination of alleles from that of either parent, resulting from one or more crossovers in prophase 1 or meiosis
recombinant
a diagram showing the relative positions of genes along a chromosome
genetic mapping
a unit of distance in a genetic map equal to the distance between genes resulting in 1% recombination
map unit
what is SRY
sex determining region in the Y chromosome
what happens if SRY is present
male structures complete their development and females structures degenerate
what happens is SRY is absent
male embryonic structures degenerate and female structures complete their development
a gene that is present in the region of the Y chromosome that shares no homology with the X chromosome
Y linked genes
the particular combination of alleles present in any defined region of a single chromosome
haplotype/haploid genotype
the principle molecule of biological heredity, a polymer of nucleotides
DNA!
what carries our most essential activities in a cell?
proteins
what does virulent mean?
causes illness or death
what is at the 3’ end
a free 3’ hydroxyl
what are the three parts of a nucleotide?
- 5 carbon sugar
- base
- Phosphate group (1 or more)
what is at the 5’ end
a free 5’ phosphate
A and T are held together by
2 hydrogen bonds
what are two ways the double helix can be described?
- a ribbon model with the backbones as ribbon
- a space filling molecules in which the atoms are shown as solid spheres
what makes DNA and RNA different?
DNA does not have an oxygen on the 2’ carbon on the sugar
RNA does have an oxygen on the 2’ carbon on the sugar
the larger of two uneven grooves on the outside of a DNA duplex
major groove
G and C are held together by
3 hydrogen bonds
the smaller of two unequal grooves on the outside of a DNA duplex
minor groove
what are three structural features of DNA
- DNA is made up on subunits called bases
- DNA is a linear polymer of nucleotides with sugar subunits linked by phosphodiester bonds
- Cellular DNA is a double helix with two strands that are antiparallel to each other
what are pyrimidines
T, G, U single ringed structures
what are purines
A and G, double ring structure
the production of a functional gene product such as a protein
gene expression
transcription and translation are two products of…
gene expression
RNA to DNA: two examples are
AIDS and HIV
RNA to RNA: two examples are
SARS or COVID
the synthesis of RNA from a DNA template
transcription
synthesis of a polypeptide chain corresponding to the coding sequence present in a molecule of messenger RNA
translation
where does transcription and translation happen in prokaryotes?
both in cytoplasm
where does transcription and translation happen in eukaryotes
transcription: in nucleus
translation: in cytoplasm
which is more stable DNA or RNA? and why
DNA is more stable since RNA has hydroxyl group which are reactive and unstable functional groups
what are the three steps of transcription and explain
- initiation: DNA polymerase are other proteins come to the double stranded DNA, DNA strands are separated, transcript of the template strand begins
- Elongation: nucleotides are added to the 3’ end of the growing RNA transcript as the RNA polymerase proceeds along the template strand
- Termination: RNA polymerase encounters a sequence in the template strand that causes transcription to STOP and RNA transcript is released
where RNA polymerase and other proteins bind to DNA, regions of a few hundred base pairs
promoters
a DNA sequence at which transcription stops and the transcript is released
terminator
genes that are constantly being expressed
housekeeping genes
a protein that associates with RNA polymerase that facilitates its binding to specific promoters
sigma factor
a complex of proteins that interacts with Pol II complex and allows transcription to begin
mediator complex
a protein that binds to the promoters of a gene whose combined action is necessary for transcription
general transcription factor
a protein that binds to a sequence in DNA to enable transcription to begin
transcriptional activator protein (TAP)
a specific DNA sequence located upstream, downstream, or within a gene that is necessary for transcription
enhancer
so what are the four things we need to initiate transcription in eukaryotes?
- transcriptional activator proteins
- mediator complex
- RNA polymerase complex (Pol II)
- general transcription factors
what can be found within the RNA polymerase complex (Pol II)
transcription bubble
noncoding RNA found in all ribosomes that aid in translation
ribosomal RNA (rRNA)
noncoding RNA that carries individual amino acids for use in translation
transfer RNA (tRNA)
noncoding RNA found in eukaryotes and involved in splicing, polydenylation, and other processes in the nucleus
small nuclear RNA (snRNA)
small, regulatory RNA molecules that can cleave or destabilize RNA or inhibit its translation
microRNA (miRNA)
a type of small double-stranded regulatory RNA that becomes part of a complex able to cleave and destroy single-stranded RNA with a complementary seqeunce
small interfering RNA (siRNA)
a process in which primary transcripts from the same gene are spliced in different ways to yield different mRNAs and therefore different protein products
alternative splicing
protein coding sequence
exons
noncoding regions
introns
what are the five types of noncoding RNA?
- rRNA
- tRNA
- snRNA
- miRNA
- siRNA
molecules of mRNA that code for multiple proteins
polycistronic mRNA
a group of genes with related functions, usually resulting from multiple rounds of duplication and divergence
gene family
what are the four types of point mutations/nucleotide substitution?
- single-nucleotide polymorphism
- Synonymous/silent mutation
- non-synonymous/missence mutation
- nonsense mutation
what are transposable elements/transpoons
a DNA sequence that can replicate and move from one location to another in a DNA molecule (some mutations are due to an insertion of a transposable element)
what are the five things in an amino acid?
- alpha (carbon)
- amino group (-NH2)
- carboxyl group (-COOH)
- hydrogen atom (-H)
- R group
what are the types of amino acids and explain
- hydrophobic amino acids: do not interact with water, do not form hydrogen bonds, they have nonpolar R groups
- hydrophilic amino acids: form hydrogen bonds, polar R groups, they lose a proton and become positively charged
- Special amino acids: effect on protein structure (glycine, proline, cysteine)
what is a peptide bond between
carboxyl group and amino acid
what are amino acids linked together by
peptide bonds
explain the four protein structures
primary protein structures: sequence of amino acids
secondary protein structures: hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern (there are alpha and beta and both stabilized by hydrogen bonds along the backbone)
tertiary protein structure: three dimensional folding pattern of a protein due to side chain interactions (3 models: ball and stick, ribbon model, space filling model)
quaternary protein structures: protein consisting of more than one amino acid chain, polypeptide subunits may be identical or different (ex. HIV two same polypeptides, hemoglobin to different polypeptides)
what are the three parts of translation and explain
initiation: initiator AUG codon is recognizes and Met is established as the first amino acid in the polypeptide chain
elongation: amino acids are added to growing chain
termination: amino acids stop getting added to polypeptide chain and is released from ribosome
what is an initiation factor
a protein that binds to mRNA (helps translation begin)
a protein that breaks the high energy bonds of the molecule GTP to provide energy for ribosome movement and elongation of the growing polypeptide chain
elongation factor
a protein that causes a polypeptide chain to be freed from its ribosome
release factor
the process by which proteins end up where they need to be in the cell to perform their function
protein sorting/targeting
an amino acid sequence in a protein that directions the protein to its proper cellular compartment
signal sequences
a peptide signal sequence that travels proteins to move from the cytoplasm of a cell through nuclear pores into the nucleus
nuclear localization signals
why do traits differ
genetic variation and environment
what is our genotype?
the genetic makeup of a cell or organisms; the particular combination of alleles present in an individual
any genetic difference among individuals that is present in multiple individuals in a population (result of mutation that spread through population)
polymorphisms
two copies of the same allele in a gene
homozygous
two different alleles of a gene
heterozygous
individuals observable characteristics or traits
phenotype
three broad types of mutations and explain
- harmful mutations: affect our ability to survive and reproduce
- neutral mutation: does not affect survival or reproduction
- beneficial mutations: improve the chance of survival and reproduction
a genetic site in the genome that is especially mutable
hotspot
a reproductive cell that produces gametes, mutations are transmitted to the next and future generations
germ cell
non-productive cell, the most common type of cell, mutations are no transmitted to future generations, they also have the greater rate of mutations
somatic cell
the analysis of a small quantity of DNA to uniquely identify an individual, also called DNA finger printing
DNA typing
a region along a DNA molecule in which many identical copies of a short sequence of nucleotides are adjacent to one another
tandem repeat
process of creating genes from duplicates of old ones
duplication and divergence
a region of a chromosome that is present twice instead of once
duplication
a mission region of a gene or chromosome
deletion
a protein that recruits the components of the transcription complex to the gene, has two binding sites, binds near enhancer
regulatory transcription factors
a protein that binds to the promoter of a gene whose combined action is necessary for transcription
general transcription factors
DNA sequences that binds with regulatory transcription factors and repress transcription
silencers
regulation of gene transcription by means of multiple transcriptional factors acting together
combinational control
the % of cases in which both members of a par of twins show the trait when it is know that at least one member shows it
concordance
twins that came from a single fertilized eggs, after several rounds of cell division, they are separated into two distinct but genetically identical embryos
monozygotic (MZ), identical twins
twins that arise form 2 separate eggs produced by double ovulation, fertilized by 2 sperm
dizygotic (DZ), fraternal twins
the transfer of info among individuals through learning or imitation
cultural transmission
with regard to complex traits, the principle that offspring exhibit an average phenotype that is intermediate between their parents and the population
regression towards the mean
unequal effects of the environment on different genotypes, resulting in different phenotypes
genotype by environment
a complex trait that is influenced by many genes and the environment and that is measurable along a continuum (ex. height and weight)
quantitative traits
