Bio Test 2

neutrophils

white blood cells that secrete DNA to trap pathogens

how were nucleic acids discovered and how did they know it wasn’t a protein

on a bandaid with pus, it had phosphorous and it didn’t dissolve in pepsin like proteins do

chromosome

condensed DNA

chromatin

loosely packaged DNA + protein

what did the griffith experiment identify and how

identifies a particle gets transferred from dead S cells to R cells but they didn’t know it was DNA, living S cells (pathogenic) mouse dies, living R cells (non-pathogenic) mouse lives, heat killed S cells (non-pathogenic) mouse lives, mix of heat killed S cells and live R cells mouse dies

DNA from the capsule of S cells transfers to R cells

R vs S cell

R cell is rough, doesn’t have a capsule, non virulent

S cells are smooth, have a capsule, virulent

How was it found that the DNA from S cells is lethal

Proteinases, ribonuclease, and deoxyribonuclease were added to the mixture and only deoxyribonuclease was not lethal (it got rid of the DNA)

how does the phage life cycle work

phage attaches to bacteria and injects its DNA into the host cell, DNA hijacks the bacteria to replicate the phage genome, phage DNA is replicated until the host cell burts and releases new phages 

What does the hershey chase experiment determine

DNA alone is sufficent for inheritance

difference in DNA and RNA (and their full names)

DNA: deoxyribonucleic acid

RNA: ribonucleic acid

RNA has one more OH group than DNA (deOXY) on the sugar

what is a nucleotide and what is it made of

phosphate group, sugar, and nitrogen base it’s the monomer of DNA and RNA

what is a nucleoside

the sugar and nitrogen base of a nucleotide

what are the different nitrogen bases

Pyrimidines: cytosine, thymine, and uracil

Purines: adenine and guanine

what nitrogen bases does DNA vs RNA have

DNA: C,G,A,T

RNA: C,G,A,U

how are nucleotides connected

the phosphate group and the sugar molecules bind

5’: phosphate group

3’:hydroxyl group from sugar

what does chargaffs experiment say

found that G&C and A&T match in DNA so they should share the same percent in the DNA

whats easier to break, Guanine and cytosine or Adenine and thymine

A+T because they only have 2 bonds

what method is used to replicate DNA

semiconservative model

DNA polymerase III

the protein that synthesizes the new DNA strand

what side of DNA can bases be added to

the 3’ hydroxyl group

what are the enzymes in DNA replication

primase, helicase, single strand binding protein, topoisomerase, DNA polymerase III, DNA polymerase I, DNA ligase

what does primase do

synthesizes a short RNA primer at the 5’ end of the leading strand and at the 5’ end of each Okazaki fragment of the lagging strand

what does helicase do

unwinds the H bonds in parental double helix (this reaction consumes energy)

what do single strand binding proteins do

binds and stabilizes single strand DNA until it’s used as a template

what does topoisomerase do

releases the tension when helicase spits 2 strands out

what does DNA polymerase III do

using the parent strand as template, it synthesizes new DNA strand by adding nucleorides to an RNA primer or existing DNA strand

what does DNA polymerase I do

removes RNA nucleotides of primer from 5’ end and replaces with DNA nucleotides

what does DNA ligase do

joins the Okazaki fragments of lagging strand, joins 3’ end of DNA that replaces primer to the rest of leading strand DNA

leading vs lagging strand

leading strand is synthesized in the 5’—> 3’ direction while the lagging strand is synthesized in Okazaki fragments 3’—>5’

what is the holoenzyme

enzyme made of multiple subunits with diverse functions, quaternary structure

what is telomerase 

the enzyme that fills the missing piece that DNA polymerase I takes off of the end of the DNA strand 

what is a telomere

the end of chromosome that only holds useless information

How many times does DNA polymerase pair 2 incorrect bases

1/100,000

what enzymes are used to fix inaccurate base pairings

nuclease, DNA polymerase, and DNA ligase

what are the two main phases of a cell

interphase and the mitotic phase

what are the stages of interphase

G1: metabolic activity and growth

S: metabolic activity, growth and DNA synthesis

G2: metabolic activity, growth, and prep for cell division

what are the stages in the mitotic phase

mitosis(distribution of chromosomes into 2 daughter nuclei)  and cytokinesis (cytoplasmic division)

what happens in DNA replication

parental strands separate and new complimentary strands form (happens in S phase)

how many pairs of chromosomes do humans have

23

chromosome, vs sister chromatid, vs homologous chromosome

chromosome is 2 identical sister chromatids, homologous chromosomes are two identical chromosomes

How many chromatids are there in G1 vs G2

46 chromatids in G1 92 chromatids in G2, 

what needs to happen to chromatin before cell division

it needs to condense

what are the two enzymes used in mitosis for chromosomes

cohesin holds the sister chromatids together before anaphase

separse frees the chromatids from each other in anaphase

steps in mitosis

prophase (early mitotic spindle forms between centrosomes and migrate toward opposite poles)

prometaphase (centrosomes on opposite sides, all microtubules form and kinetochore attaches at the centromere)

Metaphase (chromosomes line up at the middle

anaphase (microtubules pull chromosomes apart making daughter chromosomes)

how many homologous chromosomes, chromosomes, and chromatids are there in prophase, prometaphase, and metaphase vs anaphase

prophase, prometaphase, and metaphase has 3 homologous chromosomes, 6 chromosomes, and 12 chromatids

anaphase has 6 homologous chromosomes, 10 chromosomes, and 12 chromatids