Bio 5A- Dna Replication · Pcr · Mitosis And Meiosis

Front 1

Where does replication begin?
What happens here and how?

Back 1

replication origin.
the helix has become unwound in a small region. In theelectron microscope these look like ‘bubbles’ in the DNA. This process requires energy and is performed byenzymes called helicases. In the exposed single-stranded regions, new DNA can be synthesized

Front 2

Each replication origin consists of _____ .

Back 2

two replication forksmoving in opposite directions.

Front 3

What is DNA polymerase and what does it do? What does it require?

Back 3

The enzyme that directs new synthesis of DNA is calledDNA polymerase. DNA polymerase provides anenvironment in which the correctnitrogenous base can be aired with the next base in the template.
This enzyme requires a template, a free3’OH, and deoxyribonucleoside triphosphates (dNTPs)

Front 4

WHat does a primer do and how is it synthesized?

Back 4

afree 3’OH is provided by a primer that is actually made ofRNA. This primer is synthesized by a specialized RNApolymerase called a primase, which can incorporate newribonucleotides without a pre-existing 3’OH.

Front 5

What drives the reaction between the 3’OH on the ribose sugar and thephosphate group joined to the 5’carbon on the incoming nucleotide?

Back 5

The energy of hydrolysis of thepyrophosphate (PPi) drives thereaction.

Front 6

memorize this (flip)

Back 6

Front 7

Which is the leading strand? which is the lagging? Where is synthesis continuous?

Back 7

leading is on the 5'-3' end of the DNA. The leading strand is thus created from the DNAs 3' end to the 5'. The lagging is the exact opposite.
Synthesis is continuous on the leading strand

Front 8

Why is synthesis not continuous in the lagging strand?

Back 8

not continuous becauseof the need to polymerize in the 5’ to 3’ direction so a new single strandeed DNA is exposed and new primers must be made.

Front 9

What are okazaki fragments?

Back 9

The regions representingRNA primers and new DNA, with gaps.

Front 10

What is the final step? This final step is catalyzed by______ and requires energy from ______.

Back 10

The final step is replacing the RNA primers with DNA.
DNA ligase, ATP

Front 11

What is PCR? What is the goal?

Back 11

Polymerase Chain Reaction. goal: generate large amounts of a particular double-strandedregion of DNA, starting with very little initial material, or from a complex mixture of material that includesthe DNA of interest plus a large amount of undesired DNA.

Front 12

What are the three steps of PCR? Briefly describe.

Back 12

Denature: heat to 95 C
Annealing:cool 55 C to allow oligonucleotide primers to anneal complementary single stranded regions of DNA
Extend: 3’OH ends ofannealed primers are extended by the activity of a DNA polymerase and dNTPs

Front 13

Applications of PCR?

Back 13

amplification of gene wo cloning.
creating 'DNA fingerprint' for forensic science or paternity tests.
identifying pathogens
genetic predisposition

Front 14

Immediately following DNA replication, each _______ will consist of two ________ joined at a ________.

Back 14

chromosome, sister chromatids, centromere

Front 15

What is a ploidy? If you carry two complete copies of your genome you are considered a ______, abbreviated _____.

Back 15

The number of copies of the complete genome in a cell.
diploid, 2n

Front 16

What is the total # of chromosomes in most of our body cells? Where do we get our chromosome pairs from ?

Back 16

2n= 46. 1 from mom, 1 from dad.

Front 17

What are homologous chromosomes? Homologous chromosomes have the same _____ in the same locations, but might differ in the ______.

Back 17

The two members of a chromosome pair.
genes, alleles

Front 18

What is a zygote? what does it do and how does it do this?

Back 18

a single cell 2n=46 created by the fusion of sperm and egg (fertilization), will replicate manytimes over to generate the ~10^14 cells in the human body. The process that accomplishes this is mitosis

Front 19

True or false? all cells in our bodies carrythe complete genome

Back 19

True

Front 20

Mitosis creates two types of cells, what are they? What is the starting cell and end product of meiosis?

Back 20

Soma and germ.
Start: Germ cell, End: gametes

Front 21

Differences and similarities between meiosis and mitosis?

Back 21

Front 22

Describe Meiosis.

Back 22

One parent cell (a "meiocyte") duplicates its DNA and undergoes through two sequential divisions("Meiosis I" and "Meiosis II"), resulting in four meiotic products that have half as many chromosomes as thestarting meiocyte. Meiosis has to occur in diploid (2n) cells -- the meiotic products will always be haploid(n).
Mitosis can occur in haploid or diploid cells, but the number of chromosomes in the daughter cells isalways the same as the parent cell.

Front 23

What does the cell cycle look like? what are its components (5 or 2) ?
What happens during interphase?
What is cytokinesis?

Back 23

during interphase, cells carryout metabolism and growth.
cytokinesis= cell division

Front 24

What happens during each phase of mitosis?

Back 24

interphase: DNAis replicated, chromosomes begin to condense(become more tightly wound), and structures calledcentrosomes divide
prophase:centrosomes move apart and generate the spindle,the nuclear envelope begins to break down, and DNAbecomes more condensed (visible as two sisterchromatids joined at a centromere
metaphase: the chromosomes (now at their mostcondensed) are moved to the metaphase plate.
Anaphase: , the centromeres divide and the daughterchromosomes are segregated to opposite poles of thecell

telophase:, the DNA becomes decondensed,the nuclear envelope reforms, and cytokinesis follows soon after

Front 25

what does it look like?

Back 25

Front 26

Meiosis produces....

Back 26

four haploid (n)meiotic products

Front 27

What happens in each step of meiosis?

Back 27

prophase I: closeassociation of homologous chromosomesthrough a pairing process called synapsis.During this close association of chromosomes, a reciprocal exchange event called crossing over occurs
metaphase I:. The paired homologous chromosomes (bivalents)line up at the metaphase plate, and the homologous chromosomes segregate from one another. Thecentromeres do not divide
anaphase I: homologous chromosomes move to the opposite poles of the cell.
Telophase I and Cytokinesis: the cell divides
Metaphase II: very similar to metaphase in mitosis.

Front 28

True or false? There is DNA synthesis in mitosis and meiosis.

Back 28

False. not in meiosis.

Front 29

reductional division vs equational division

Back 29

Because meiosis I results in a halving of chromosome number (2n -> n), it is called the reductional division,while meiosis II is called equational (n -> n).