Ch 6/7 DNA and Gene Expression, Biotechnology

DNA is composed of…

deoxyribose (sugar), phosphate, nitrogenous bases (A-T, C-G)

In DNA, the sugar-phosphate part of nucleotides… (test question!)

makes the double helix backbone of the two strands

In DNA, two strands of nucleotides are held together by…

hydrogen bonds between the bases, with specific base pairing (A-T, C-G)

genome

an organism’s complete set of DNA

chromosome

one or more unique pieces of DNA. DNA attaches to this

gene

a specific sequence of DNA that codes for s specific protein

locus

location of a gene on a chromosome

alleles

different versions of a gene that occur at a specific locus and code for a specific trait

trait

any single characteristic or feature of an organism

DNA is the code, RNA decodes it through ____ .

transcription (def)

a lot of DNA is “____”, containing repeats and fragments

noncoding

introns

noncoding segments within coding segments

genotype

the genes that an organism carries for a particular trait (ex. the specific “recipe” in a cookbook)

phenotype

the physical manifestation/appearance of the genes for particular trains (ex. the food item made from the “recipe”)

transcription (term)

a copy of gene’s base sequence is made

translation (term)

the copy of a gene’s base sequence is used to direct the production of a polypeptide

step 1 of transcription: recognize

RNA polymerase binds to a promoter site on a gene

step 2 of transcription: transcribe

RNA polymerase makes a copy of the gene by using the base-pairing rules but substituting U for T (instead of A-T in DNA)

step 3 of transcription: terminate

RNA stops making a copy when it encounters a stop code

step 4 of transcription: cap and edit

the copy has extra bases added to the front (cap) and end (tail) to provide protection. Noncoding pieces are removed.

transcription makes a copy called ____ , and after step 4 it moves out of the nucleus.

mRNA (def)

transcription occurs in the…

nucleus

start codon(s)

AUG

stop codon(s)

UAA, UAG, UGA

translation occurs at the…

ribosomes

step 1 of translation: recognize and initiate

the ribosome and the tRNA carrying AUG (start codon) bind to the start sequence on the mRNA.

step 2 of translation: elongate

the ribosome continues down the mRNA, binding tRNA and binding amino acids according to codons

step 3 of translation: terminate

the ribosome will encounter a “stop” codon and the mRNA and completed protein will be released from the ribosome

mRNA (term)

messenger RNA

tRNA (term)

transfer RNA

gene expression

the production of the protein that the genes sequence codes for

gene regulation

whether a gene is turned on or off. Stops cancer.

regulatory proteins

positive control: initiates or speeds up gene expression

negative control: slows or blocks gene expression

operon

a group of several genes, along with the elements that control their expression as a unit

promoter

where RNA polymerase binds during transcription

operator

a regulatory region to which a repressor can bind

regulatory gene

codes for the repressor that binds to the operator

RNA polymerase

an enzyme that synthesizes RNA from a DNA template during transcription

mutation

an alteration to the sequence of bases in DNA

substitution mutations

“spelling” errors with the wrong base

insertion mutations

an extra base

deletion mutations

missing a base

chromosomal aberration: deletion

gene missing

chromosomal aberration: relocation

gene in the wrong place

chromosomal aberration: duplication

extra copies of a gene

primary causes of mutations

spontaneous, radiation induced, or chemical induced

biotechnology

the use of technology to modify organisms, cells, and their molecules to achieve practical benefits

modifying organisms: chop

cutting out and isolating a gene of interest using restriction enzymes

modifying organisms: amplify

polymerase chain reaction (PCR) makes billions of identical copies of an isolated gene of interest

modifying organisms: insert

using plasmids to transfer DNA from one organism to another. The gene of interest carried on the plasmid is transferred to a bacterial cell. Now in a living cell, the gene can be transcribed and translated to produce the protein product.

modifying organisms: grow

creating a gene library. The bacteria are grown on nutrients, passing genes of interest along as they divide.

CRISPR-CAS9

derived from a natural bacterial immune mechanism that “remembers” viral DNA and uses this precise gene information to cut up future viral invaders.

genetic engineering

manipulation of a specie’s genome in ways that do not normally occur in nature

recombined DNA technology

combination of DNA from two or more sources into a product

GMO’s

genetically modified organisms. produced with recombinant DNA technology. AKA transgenic organisms

transgenic organisms

modified organisms carrying gene(s) of interest

human growth hormone (HGH)

stimulates growth and protein metabolism, can be used to treat dwarfism

gene therapy

inserting a functional gene into an individual’s cells to replace a defective version of the gene. A difficult and complicated process.

cloning

creating a new individual with a genome identical to the donor individuals

DNA fingerprinting

99.9% of DNA from two individuals is the same. Short tandem repeats (STRs) are sequences of DNA that repeat over and over again. They occur in some of the most highly variable regions of an individual’s DNA. The number of STRs differs between individuals.

Short tandem repeats (STRs) [likely test question]

are sequences of DNA that repeat over and over again. They occur in some of the most highly variable regions of an individual’s DNA.

DNA polymerase

an enzyme that synthesizes new DNA strands from a template