Genetics Test 1 (BIOL2301)

Dependent variable

What you are measuring/what you care about/the outcome/the effect

Independent variable

what you are manipulating (in hopes of affecting the dependent variable/ the potential cause)

What are controls

controls provide predictable outcomes

negative control

Independent variable will not affect dependent variable, tells us baseline information about dependent variable

positive control

independent variable will affect dependent variable in measurable way

Experimental/Treatment

unknown outcome, what you are testing

Standardized variables

Things that are kept the same for treatment and control groups to isolate cause and effect

Frederick griffith

1928- mixing harmless bacteria with material from heat killed dangerous bacteria.

Oswald, macleod, mccarty

Enzymes that destroy DNA and proteins

When something ends in “ase”

An enzyme

order of the central dogma

Replication, dna, transcription, rna, translation, amino acid chain, folding, protein

List some functions that depend on proteins

Movement, structure, defense, transport

What are proteins

linear chains of amino acids which fold to make complex shapes capable of doing a specific task in the cell

What determines the proteins shape and abilities

The order of specific amino acids

What causes sickle cell disease

A difference in the 6th amino acid

What is DNA made of

Two strands of nucleotides

What type of bonds link the nucleotides in strand

Covalent bonds

What type of bonds hold the two strands together

Hydrogen bonds

How many kinds of nitrogenous bases

four different possible nitrogen bases

What are the different nitrogen bases

Thymine, Cytosine, Adenine, Guanine

Which bases are pyrimidines

Thymine and cytosine

Which bases are purines

adenine, guanine

What group is at the 5’ carbon atom

5’ phosphate group

What group is at the 3’ carbon atom

3’ hydroxyl group

What is the backbone on a DNA strand made of

A sugar phosphate backbone

How are strands made/attached

5’ phosphate to 3’ OH of next nucleotide creating a strand with a 5’P end and 3’ OH end.

Information of DNA is stored in…

order of nitrogenous bases

What did Erwin Chargaff discover

1952- A is equal to T, G is equal to C

What is base pairing

A purine with a pyrimidine, adenine with thymine, guanine with cytosine

What is the structure of DNA

Double helix, Anti-Parallel strands (one strand 5’ to 3’, the other 3’ to 5’)

What is the most common form of DNA

B- DNA

What are the different kinds of DNA

B-DNA, A-DNA, Z-DNA

Which helixes are right handed

A and B

Which helixes are left handed

Z DNA

What is the major groove side in base pairing

more access to nitrogen bases

What is the minor groove side in base pairing

More access to sugar phosphate group

What can guanine rich DNA sequences form

G-Quadraplex structure

What does underwinding create

Underwinding DNA can assist in separating strands (right hand crossing)

What does overwinding create

Positive supercoils, left hand crossing

What is the function of topoisomerase

Can change winding/coiling

Function of topoisomerase 1

Make a single-stranded break in the DNA double helix and reseal the strand.

Function of topoisomerase 2

Make double-stranded breaks in the DNA double helix and reseals the strands using ATP

Define genome

The full hereditary information for an organism, a complete set of its DNA

Define chromosome

A large, continuous DNA molecule (or 2 joined identical DNA molecules following DNA replication)

What are genomes made of

Made of one or more chromosomes

Describe prokaryotic cells

before nucleus, in the archaea and eubacteria, smaller, DNA stored in the cytoplasm, single celled

Describe eukaryotic cells

true nucleus, DNA stored in nucleus surrounded by membrane, little organelles surrounded by membranes with specialized jobs, larger, multi celled organisms

Does genome size correlate with organismal complexity

No.

What are histone proteins

provides structural support for the DNA (packs the middle)

What is chromatin

Mixture of DNA and proteins that pack long DNA strands into the nucleus.

What forms the nucleosome

DNA wrapped around histone proteins

Define chromosome condensation

When DNA is more tightly packed, the genes are less likely to be read to make proteins

Define euchromatin

loosely packed DNA actively being read to produce proteins

Define heterochromatin

Tightly packed DNA not being read

What does acetylation of proteins do

Acetylation of histone proteins loosens DNA packing.

Describe what unacetylated histones look like

Tightly packed histones

Describes acetylated histones

loosely packed histones

What does methylation of histone proteins do

Tightens DNA packing

Describe RNA structure

single stranded

Which nitrogen base is different in RNA

RNA has uracil instead of thymine

Which nitrogen base does Adenine pair with in RNA

Uracil instead of thymine

What sugar is in DNA

deoxyribose, deoxyribonucleic acid

What sugar is in RNA

Ribose, ribonucleic acid

Can RNA base pair with itself?

Yes, can pair with itself or with DNA

Before cell division what must DNA undergo…

Replication to make two identical copies for the daughter cells

What allows for simple replication of DNA

complementary strands

define origin of replication

specific sites (sequences) where DNA replication starts

Define replication bubble

expanding area of replicated DNA

Define replication fork

site of active replication, two per replication bubble

To which end can DNA polymerases add new nucleotides

to the 3’ end

What is the function of DNA polymerases

add new nucleotides to the 3’ end

Where does the energy to add a new nucleotide come from

ATP from last connection powers the new connection

Define proofreading

Replacing an incorrect nucleotide just placed by polymerases

What two factors allow for DNA proofreading

3’ to 5’ exonuclease capability (only adding to the 3’ end)

Define exonuclease

Cuts nucleotides off end of nucleic acid strand

Explaining why only adding nucleotides to the 3’ end allows for proofreading. Why not the 5’ end?

Adding to the 3’ end one group leaving can power the next group. adding to the 5’ end as no energy and can only be done once.

Define the function of DNA Helicase and the problem it creates

unwinds double-stranded DNA but overwinds the DNA in front of it, requiring the action of topoisomerase

Define function of primase

Builds short RNA strands called primers that DNA polymerase can work from to build a DNA strand. Primase binds to the template strand and syntehsizes an RNA primer.

Describe the leading strand

synthesized toward the replication fork continuously.

Describe the lagging strand

Synthesized away from the replication fork in series of okazaki fragments

Define DNA polymerase III

main DNA polymerase 5’ to 3’ polymerase and 3’ to 5’ exonuclease for proofreading

Define DNA Polymerase III

Main DNA polymerase 5’ to 3’ polymerase and 3’ to 5’ exonuclease for proofreading

AND 5’ to 3’ exonuclease for replacing RNA primers

Define function of DNA ligase

connects adjacent strands of DNA together to combine okazaki fragments to form one continuous new strand (glue)

What is the end replication problem

Eukaryotic linear chromosomes can never fully be replicated due to lagging strand dynamics. Chromosomes shorten during each replicative cycle

Define telomeres

non-protein coding repetitive sequence found at the ends of chromosomes. They act as a buffer to protect protein coding genes. Shorten with each replication

Define telomerase

Protein RNA complex, telomerase maintains telomere length by adding DNA sequences to the ends of the chromosomes to keep them from shortening during divison.

What is a PCR

Polymerase chain reaction, in vitro method for making copies of DNA sequences using DNA polymerase

How do PCR primers initiate replication

short DNA sequence produced synthetically and added to PCR reaction

Describe the PCR cycle

Denature bu splitting DNA strands, Anneal by reducing temp, Extended from primer

What is the temperature at which denature happens

95 degrees Celsius

What direction does DNA polymerase go?

adds to 3’ end of primer

Which base pairs can anneal at higher temps and why

GC base pairs are stronger than AT pairs so they can anneal at higher temps

What is Sanger Sequencing

Similar to PCR but only one primer is used and no chain reaction occurs. ddNTPS are there to prematurely end strand synthesis.

What is ddideoxynucleotides (ddNTPs)

Stop strand synthesis

How do you separate DNA molecules based on size/length

Gel electrophoresis using electricity to separate DNA molecules by size

What is shotgun sequencing

Break many copies of genome into small pieces, use overlaps between pieces from different copies to assemble them properly.

Define a gene

individual unit of genetic information, a section of DNA that codes for something

Define promoter DNA Sequence

marks the begining of genes on the 5’ end

What is the TATA box

In transcription is a promoter that marks where transcription begins

What are some modifications that are made after transcription

-5’ methyl G cap, 3’ poly A tail, facilitate export from nucleus, facilitate translation.