Genetics Test #1

Who was gregor medel?

“the father of genetics”

what is the central dogma of molecular biology

genetic information flows only in one direction, from DNA, to RNA, to protein, or RNA directly to protein.

what did mendel do?

he crossed peas and analysed their offspring for their inherited traits

dominant alles

produces a dominant phenotype in individuals with one copy of the allele

reccesive

to produce a recessive phenotype, the individual must have 2 copies of the gener one from each parent

which one takes over dominant or reccesive?

dominant always trumps recessive

what does it mean to be a carrier of a gene?

you have the gene so you can pass it on but the trait wont manifest physically in you

sex linked

traits determined by genes that are located on the sex chromosome

examples of sex linked traits

hemophilia,colorblindness

codominance

both alleles are expressed equally in the phenotype

incomplete dominance

neither is dominant over the other so you get an intermidiete phenotype

sickle cell dominant

the sickle cell heterozygous trait provides malaria resistance without the disease andf is therefore dominant for malaria resistence

sickle cell recessive

homozygous individuals who actually get cicle cell

sickle cell codominance

in heterozygous individuals, both normal hemoglobin and sickle hemoglobin are produced and both are expresed

f1 vs f2 true breeding

all of the f1 will have heterozygous alleles and therefore show the dominant phenotype by when you cross the f2 gen you will have a homzygous dominant and a homzygous recessive

what is dna composed of

nucleotides with 3 components, a phosphate group,a suger and a nitrogenous base (adenine (A), thymine (T), Cytosine (C), and Guanine (G))

a goes with

t

c goes with

g

how does DNA make more of itself

Dna replication

steps to DNA replication

unzip the DNA, binding of RNA primase, synthesis by DNA polymerase, elongation of the new strand, reemoval of RNA primers and sealing with DNA ligase

what does it mean if DNA is semi-conservative

ach new dna molecule has one origional paretn strand and one newly synthesized strand (half og dna)

what does it mean if the replication is bidirectional

if it starts at the origin of replication and proceeds in boh directions amlong the dna molecule making relication faster

How did taylor,woods, and hughes see that each replicated DNA had only one new strand

radiactive labeling with thymidine

What is the connection between DNA and proteins

dna contains the information that builds proteins

what dpes the biotechnological tool codetta do?

it analyses and decodes genetic information especially codon usage

how does codetta show that there is “almost nothing universally conserved across life”

by showing that even the most fundemental genetic components like codon usage vary signifigantyl across different life forms, indicating a more ocmplex evolution the previously thought

what is the purpose of a dna repair system in your genetic code

to detect and correct any erros in your dna without it mutations would accumulate and lead to disease or degrade over generations

What ground-breaking mechanism were Lindahl, Modrich, and Sancar recognized for with the 2015 Nobel Prize in Chemistry?

Dna repair specifically, base excision repair (fixes snall base lesions), necleotide exicison repair (removed large helix distorting lesions like UV light injuries), mismatch repair (corrects errors during DNA replication)

what process do cells use to repair Dna damage

base excison repair, neucliotide excision repair, and mismatch repair

what common type of mutation arises during dna replication

point mutations are common and occur when DNA polymerase inserts a wrong base that is not immedietly corrected

how does DNA proofread itself

DNA polymerase has proofreading ability

If error exists after proofreading,what mechanism is activiated

the mismatch repair which identifies mismatches that were not fixed by the polymerase

what is the funtion of the colon

absorbs water and electrolytes fro material and sores waste before its expelled

how does colon cancer begin

usually cancer begins through polyps that develop and become cancerous over time

how to look for polyps

you get a colonoscopy

how is a pedigree built

by making a chart of disease within a family

how is a pedigree anaysed

By observing patterns of traits across generations (e.g., whether traits appear in every generation or skip generations), one can determine if a trait is autosomal dominant, autosomal recessive, sex-linked, or another type of inheritance pattern.

what is the HNPCC inheritence pattern

it has an autosomal dominat pattern of inheritance, meaning ing if they have 1 copy of the mutated gene they have an increased risk of developing colerectal cancer

why statrt with a pedigree?

ihelps identify family members who may carry the mutation and are at risk for HNPCC. It reveals patterns that suggest which individuals should undergo further testing.

why do genetic testing?

to confirm the presence of the hnpcc mutation to begin treatment

how are mutated individuals identified

genetic testinng (usually of mismatch repair genes)

why are hnpcc mutation individuals at a greater risk for colorectal cancer

becuase the gene impedes their ability to repair their genes, leading to an accumulation of errors and mutation increasing the risk of cancers

hwo does gelelctropherisis work

it spertates dna by size by applying a current to DNA samples loaded into a well within a gel .

Since Dna is negatively chargefd it moves towards the…

positie electrode

smaller dna fragments move…

fatster and further in the gel

large dna fragments move…

slower and less in a gel

what is the proper precidure to use a micropipette

apply tip, pace plunger to first stop and then insert in liquid and then release to draw up sample, dispense by pushing to the second stop, dispose of tip

whta role does a restricition enzyme play in preparing dna to run in a gel

cuts DNA at specific sequences, creating fragments that can be separated by gel electrophoresis.

WHy was APO1 used with bobs family?

becuase it cuts DNA at sights with the HNPCC mutation whcih will make the mutated DNA shorter, moving faster, and therefore easier to identify

How do you analyse a gel to make sense of it?

After staining, dna fragments are visualized under a uv lights and then compared to a dna ladder

what is the HNPCC mutation

a mutation on MSH2 when a guanine becomes an agenine

what is the origiona MHS2 sequence

TAGATTTC

ATCTAAAG

what is the HNPCC MSH2 sequence

TAAATTTC

ATTTAAAG

okazaki fragments

Okazaki fragments are short DNA segments formed on the lagging strand during DNA replication.