UNIT 1 GENERAL BIOLOGY Q3

Central Dogma

describes the flow of genetic information in cells from DNA to messenger RNA (mRNA) to protein

Replication, Transcription, Translation

3 processes in Central Dogma

polynucleotides

Nucleic acids are polymers called __________.

nucleotides

Each polynucleotide is made of monomers called ____________________.

nitrogenous base, a pentose sugar, and a phosphate group

Each nucleotide consists of a __________.

nucleoside

The portion of a nucleotide without the phosphate group is called a __________.

2nd carbon

DNA does not contain oxygen in the _________.

Phospate

found at the end, the same in both DNA and RNA

Sugar

found at the end of the DNA.

Nitrogenous Base

rods of the DNA

Adenine Thymine Cytosine Guanine

Nitrogenous Bases in DNA

Adenine Uracil

Pyrimidine

single six-membered ring

Purine

six-membered ring fused to a five-membered ring

Nucleotide polymers

______________ are linked together to build a polynucleotide.

anti-parallel

DNA strands are __________ - runs alongside each other bit on different directions.

DNA

found only in the nucleus

RNA

can be found in both nucleus and cytoplasm

Conservative Replication

original parent double strands remain intact and two completely new double helix strands are synthesized ; the new strand is 100% new.

Semi-conservative Replication

the two strands come apart – each acts as a template for synthesis of a new complementary strand ; the new strand is 50% old, 50% new.

Dispersive Replication

both original parent strands are broken up into small pieces and incorporated into newly synthesized strands ; mix of original and new

Origin of Replication

special sites where the replication of a DNA molecule begins wherein the two strands are separated.

Prokaryotes

has circular DNA ; one origin of replication ; 1 bubble 2 forks

Eukaryotes

has linear DNA ; multiple origins of replication ;

Helicase

protein in eukaryotes that unwinds and separates parent strands

Topoisomerase

protein in eukaryote that smoothens strain

Single strand binding proteins

protein in eukaryote that is used to stabilize ; “hair clip”

Primase

protein in eukaryotes that jump start the process of replication

DNA Polymerase

catalyzes the elongation of new DNA at a replication fork

DNA Polymerase 1

replaces the RNA primer with DNA

DNA Polymerase 3

main enzyme for DNA elongation

anabolic

DNA replication is _________.

Triphosphate

The incoming nucleotide has three phosphate groups attached to it. _______ stores energy that is needed for the binding reactions to happen.

Deoxythimidine triphosphate (dTTP)

Deoxycytidine triphosphate (dCTP)

Deoxyadenosine triphosphate (dATP)

Deoxyguanosine triphosphate (dGTP)

Types of Triphosphates

Anti-parallel Elongation

one strand is synthesized in the 5′ to 3′ direction while the other is synthesized in the 3′ to 5′ direction

Leading Strand

follows helicase ; can synthesize continuously

Lagging Strand

away from replication fork ; synthesized as Okazaki fragments

Okazaki Fragments

series of segments ; replaced with DNA polymerase 1

DNA Ligase

connects the Okazaki fragments ; finishes the synthesis

mRNA

instructions on DNA are transcribed onto ________.

Ribosome

reads mRNA ; uses info to string amino acids together into proteins

wrong until END

if DNA is wrong = ________

break down RNA

if RNA is wrong = ________ to form a correct one

simultaneously in the cytoplasm

In prokaryotes , transcription and translation happens _________.

nucleus ; cytoplasm

In eukaryotes , the transcription happens inside the ______ and the translation happens in the ______.

Codons

nucleotides in an mRNA sequence code for amino acids

64

How many possible codons are there?

UAA, UAG, UGA

What are the stop codons?

Reading frame

refers to which nucleotide starts the first codon

6

For each segment of DNA, how many possible reading frames are there?

DNA Transcription

gene’s DNA sequence is copied to make an RNA molecule

DNA Transcription: Initiation

RNA polymerase binds to promoter ; has helicase activity

DNA Transcription: Elongation

polymerase moves downstream unwinding the DNA and elongating the RNA transcript 5’ - 3’ ; DNA strand re-forms a double helix

DNA Transcription: Termination

RNA transcript is released and polymerase detaches from DNA ; amino acid chain is processed

Promoters

sequence in the DNA that signals the initiation of RNA synthesis.

TATAAT and TTGACG

Most genes have ______ and ______ as promoters.

conserve energy

Not all parts of DNA are transcribed to __________.

Transcription Factors

proteins that help eukaryotic RNA polymerase recognize promoter sequences ; present in both prokaryotes and eukaryotes

40 nucleotides per second

Elongation of DNA transcription occurs at a rate of __________.

Polyribosomes

Ribosomes attach to RNA resulting in more protein products. Ribosomes move along the mRNA translating it into a polypeptide chain.

Modified Nucleotide Cap

In the processing of mRNA in eukaryotes, this is received by the 5’end (guanine).

Poly-A Tail

In the processing of mRNA in eukaryotes, this is received by the 3’ end(adenine).

RNA Splicing

removes introns and joint exons

Introns

intervening sequences that need to be removed ; evolutionary remnants that regulate how mRNA is spliced

Exons

coding sequences ; intron splicing is not the only way to splice

Alternate Splicing

introns can stay behind or leave, exons should always stay behind

Protein Synthesis

decodes mRNA to produce polypeptide

Polypeptide Formation

formed when the amino group of one amino acid forms and amide bond with the carboxyl group of another amino acid ; reaction is catalyzed by ribosomes

Translation Machinery: tRNA / Transfer RNA

consists of a single RNA strand that is only about 80 nucleotides long ; roughly L shaped ; has base pairs for stability

Translation Machinery: Ribosomes

facilitate the specific coupling of tRNA anticodons with mRNA codons during protein synthesis

Ribosomal Units

constructed of proteins and RNA molecules(rRNA)

E site

exit site of RNA

P site / peptidyl-tRNA binding

formation of peptide bonds

A site / aminoacyl-tRNA binding

holds tRNA carrying the next amino acid to be added

DNA Translation: Initiation

mRNA attaches to the smaller subunit of the ribosome. A tRNA with the appropriate anticodon attaches, then the larger subunit of the ribosome then comes in.

DNA Translation: Elongation

tRNA moves in with appropriate amino acid, then amino acid chain grows using peptidyl transferase

DNA Translation: Termination

Stop codon is reached, then amino acid chain is processed.

Genetic Engineering

a process of manipulating the genetic material of an organism to alter its characteristics or traits.

Transgenic Organism

other term for Genetically Modified Organism(GMOs)

1. Artificial Selection

2. Cloning

3. Recombinant DNA Technology

Modes of Genetic Engineering

Artificial Selection

Breeders choose which organism to mate to produce offspring with desired traits. They cannot control what genes are passed. When they get offspring with the desired traits, they maintain them.

Selective Breeding

organisms with desired characteristics are mated to produce offspring with those desired traits ; important genes are passed to next generation

Dachshunds

once bred to hunt badgers and other burrowing animals, must be small to fit into animal’s hole in the ground

Hybridization

unlike characteristics are crossed to produce the best in both organisms

Luther Burbank

________ created a disease-resistant potato called the Burbank potato.

Burbank potato

disease-resistant plant was crossed with another that had a large food-producing capactiy

Inbreeding

breeding of organisms that are genetically similar to maintain desired traits

recessive genetic disorder

In inbreeding, the chance that the offspring will get a __________ is high.

Organismal Cloning

produces one or more organisms genetically identical to parent that donated the single cell

Totipotent Cell

cell that can generate a complete new organism

Meristematic Cells

transverse sections of an organism that divide after culturing.

Nuclear Transplantation

nucleus of unfertilized egg cell or zygote is replaces with nucleus of differentiated cell

older ; lower percentage

The _____ the donor nucleus, the ______ of normally developing tadpoles.

Dolly the Sheep

a cloned lamb from an adult sheep by nuclear transplantation

Stem Cell

relatively unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of one or more types

Embryonic Stem Cells

stem cells isolated from early embryos at the blastocyst stage ; able to differentiate into all cell types

Adult Stem Cells

replace non-reproducing specialized cells ; generates a limited number of cell types

Animal Stem Cells

can be isolated from early embryos or adult tissues grown in culture

Recombinant DNA Technology

used to create new combinations of DNA molecules by combining genetic material from different sources

Human Insulin

hormone that lowers blood sugar ; absent in diabetic people