Genetics Exam 1

august 23, 2023

when was the completed sequence of the human genome finished

DNA to RNA to Protein

what is the genetic flow of information

similar but not identical

homologous chromosomes are

homologous pairs

how to do chromosomes exist as in diploid organisms

only during mitosis and meiosis, coiled & condensed

when are chromosomes visible

when all the chromosomes are condensed

when is the karyotype visible

when genetic material portioned to daughter cells during nuclear division

what is karyokinesis

where cells dont divide, highly differentiated

what is the G0 phase in the cell cycle

M phase

when do cells divide in mitosis

chromosomes coiled & condensed, centrioles divide and move apart

what is prophase of mitosis

metaphase

when do centromeres align in mitosis

two identical parts of each chromosome, connected at the centromere

what are sister chromatids

protein complex that holds sister chromatids together

what is cohesion

enzyme that degrades cohesion

what is seperase

protein that protects cohesion from being degraded by seperase

what is shugoshin

anaphase

when do daughter chromosomes migrate to opposite poles in mitosis

telophase

when does cytokinesis end

two identical diploid daughter cells

how many cells does mitosis produce

leptonema

chromosomes appear as long, single threads, unassociated

zygonema

synapsis

pachynema

each homologous chromosome becomes shorter, thicker, and spilts into two sister chromatids

prophase 1

when does crossing over occur in meiosis

diplonema

when sister chromatids separate

diakinesis

nucleus and nuclear envelope break down

cytoplasm

the oocyte has more

genotype, epigenetic events, environment

what three thing effect phenotype

gregor mendel

who laid the foundation for heredity

seven: seed shape, seed color, pod shape, pod color, flower color, flower position, stem height

how many characteristics did Mendel measure

independently

how do non-homologous chromosomes assort

9:3:3:1

what is the predicted ratio of two heterozygous parents in a dihybrid cross

RY, Ry, rY, ry

what genotypes will an RrYy parent make

probablity of two INDEPENDENT events occurring simultaneously

what is the product rule

½ X ½ X ½ = 1/8

probability of having 3 boys in a row

recessive traits

what traits can skip generations

its a recessive autosomal trait

if there is no gender bias what can you assume

occurs most frequently in nature

what is the wild type allele

mutations that cause changes in functional activity of a gene by eliminating enzyme function, changing relative enzyme efficiency, changing overall enzyme function

how do new phenotypes occur

when heterozygous offspring from a cross between parents has contrasting traits

what is an intermediate phenotype

Karl Landsteiner

who discovered blood type

both alleles are expressed equally (ABO blood types)

how does codominace effect phenotype

N-acetylgalactosamine

what does the IA allele direct to the H substance

galactose

what does the IB allele direction to the H subatance

there will be no substrate to make A or B antigens, presenting as O, donated IB

if the FUT1 allele has fucose mutation what will occur

2

how many alleles can a single gene have

only need one copy for survival, can afford to lose one but not both

what is a lethal essential gene

may kill an organism only when certain environmental conditions prevail

what is a conditional lethal allele

a dominant lethal allele

what is Huntingtons dieases’s caused by

one genes alleles mask the effects of the other

what is epistasis

enzymes coded for both genes

what do you need for epistais of both genes

pleiotropy

expression of a single gene having multiple unrelated phenotypic traits

sickle cell disease

example of pleiotropy in humans

colorblindness

X-linked gene mutation example in humans

it would be milder in females because can be covered up with other X

how would an X linked dominant trait affect females

the expression of a specific phenotype is absolutely limited to one sex

what is sex limited inheritance

only hh males will be cock-feathered

an example of sex limited inheritance

when the sex of the individual influences the expression of a phenotype that is not limited to one sex or the other

sex influenced traits are

baldness in men

an example of sex influenced traits

the percentage of individuals that show at least some degree of expression of the mutant genotype in a population

what is penetrance

the range of expression of the mutant phenotype

what is expressivity

dissimilar, X & Y chromosomes

what are heterorprophic chromosomes

by the SRY gene in the Y chromosome

where is TDF

female

what gender is someone with turner syndrome pheotycially

XXY

what is the genotype for someone with Klinefelter syndrome

helps to limit protein dosage specifically in females by producing Barr bodies (inactivation of X chromosome)

what is dosage compensation

calico cats, random inactivation

example of dosage compenstation

some are activated and some aren’t ( deletion of Tsix gene) blocking X-X pairing, causing chaotic chromosome inactivation

What does mosaic mean in X chromosome inactivation

many genes individually behaving to contribute to phenotype in a quantitative way (more dominant = darker color)

what is the multiple gene hypothesis

multiple genes contributing to a single, quantitive trait

what are polygenes

there will be more phenotype classes

if there are more poly genes…

mesures how much variation is common to two quaniatiaitve traits

what is covariance statistic

measures contribution of genotypic variance to total phenotypic variance

what is broad sense heritability m

proportion of phenotypic variance due to additive genotypic variance alone

what is narrow sense heritability

Frederick Griffith

who showed that Streptococcus pneumonia could be transformed to virulence

injecting mice with virulent, avirulent, and heat killed virulent, then avirulent with heat killed virulent and showed how the DNA from the heat killed was transformed into the virulent

what did Griffiths experiment entail

Avery, MacLeod, McMarty

who showed that the transforming principle was DNA and not protein

that DNA is not a protein, it is the genetic material through the use of phosphorus and sulfur

what did Hersey and Chase demonstrate

the process of infection by viral DNA into bacterial cells

what is transfection

at wavelength 260 nm

where is genetic material most mutagenic

recombinant DNA technology

what is the strongest direct evidence for DNA as the genetic material

RNA dependent RNA polymerase or RNA replicase

what would be needed to make a copy of RNA

RNA is the template for synthesis of a complementary DNA by RNA dependent DNA polymerase (reverse transcriptase)

how do retroviruses replicate

nitrogenous base, pentose sugar, phosphate group

what do nucleotides consist of

an OH group on carbon 2 of the pentose sugar

what is missing from deoxyribose that ribose had

nitrogenous base and a pentose sugar

what does a nucleoside contain

a nucleoside with a phosphate group

what is a nucleotide

3: NMPs, NDPs, NTPs

how many groups can phosphate groups have

by a phosphodiester bond between the phosphate groups at C-5 position and OH group on the C-3 position

how are nucleotides linked

amount of A is proportional to T and amount of C proportional to G but the percentage of C & G deosn’t have to equal A & T percentage

what is Chargaffs rule

helical, more than one strand, 10 base pairs per complete turn

what did Rosalind Franklin discover

that it is a right handed double helix in which the two strands are antiparallel and the bases are stacked on one another

what did Watson and crick propose based on DNA structure

2 H bonds

how many H bonds does A & T form

3 H bonds

how many H bonds does C & G form

some RNAs form single stranded but some can form double stranded regions as they fold into different secondary structures

is RNA double or single stranded

if there is a greater melting point then there is most likely a greater GC content since it has three bonds it requires more energy

how would GC content correlate melting point

melting/denaturing

what is the process from double stranded DNA to 2 single strands of DNA called

annealing

what is the process from 2 single stranded DNAs to one double stranded

by fluorescent in situ hybridization using fluorescent probes to monitor hybridization

how can a chromosomal location of a DNA of interest be identified

the phosphastes make them have a negative charge, moving down

why does DNA travel to the bottom (+) end of gel electrophoresis

by semiconservative replication

how is DNA reproduced

by Meson and Stahl using N15 labeled E. coli going in N14 medium

how was it shown that DNA replication is semiconservative in prokaryotes