AP Biology Unit 6 Flashcards

flashcards from this link: https://knowt.com/note/00d2ffbb-9641-466e-b96f-da4e1345e213/Unit-6-Gene-Expression-and-Regulation

What are the purines?

Adenine and guanine

What are the pyrimidines

Cytosine, Uracil, and Thymine

Plasmids

Small, double-stranded, circular DNA molecules

Phosphate bonds

Links sugar molecules in DNA

Which bonds are DNA linked by?

Hydrogen bonds

Genome

All of the DNA for a species

Chromosome

Each separate chunk of DNA in a genome

Histone

What DNA is wrapped around

Nucleosome

A group of histones

Euchromatin

When the genetic material is in a loose form around the nucleus

Heterochromatin

When the genetic material is fully condensed into coils

DNA Replication

The copying of DNA

Helicase

Breaks the hydrogen bonds of the double helix

y-shaped replication fork

The exposed DNA strands when they are unzipped by helicase

Origins of replication

The specific sites where DNA replication begins

Topoisomerases

They cut and rejoin the DNA backbone to relieve from tangling

DNA polymerase

The enzyme that adds the nucleotides to the freshly built strand

RNA primase

adds a short strand of RNA primer (creates a staring point for the DNA polymerase)

Leading strand

The strand that is made continuously

Lagging strand

The strand that is made discontinuously

Okazaki fragments

the short segments of DNA synthesized discontinuously

The build direction of the lagging strand

The opposite direction of the way that the helix is opening

DNA ligase

joins the Okazaki fragments together

Semiconservative

The DNA replicates in a way that conserves half of the original molecule in each of the two new ones

Telomeres

The unimportant sections of DNA at the ends of a molecule

What is the first step of DNA expression?

Turning it into RNA

Transcription

The process of making RNA from DNA

Translation

The process of making a protein from RNA

Order of the central dogma?

DNA - mRNA via transcription - protein via translation

mRNA

A temporary RNA version of a DNA recipe that gets sent to the ribosome

rRNA

makes up part of the ribosomes

tRNA

brings amino acids to the ribosomes

Promoters

The special sequences of the DNA where transcription begins

Start site

The official starting point of transcription

Antisense strand

The strand that serves as a template

How does RNA polymerase build RNA?

It adds nucleotides only to the 3’ side

Exons

Regions that express the code

Introns

Noncoding regions in the mRNA 

Polycistronic transcript

mRNA that codes for multiple proteins

Monocistronic

mRNA that only codes for one protein

Splicing

The process of the introns being removed and the exons linking together

Spliceosome

How splicing is achieved

What is added to the 3’ end during RNA processing?

A poly(A) tail

What is added to the 5’ end during RNA processing?

A 5’ GTP cap

mRNA to what?

Protein

Where does translation occur?

On ribosomes in the cytoplasm and on the rough endoplasmic reticulum

Codon

3 nucleotides that code for an amino acid

What do the ends of the tRNA carry?

Amino acid; anticodon

What is an anticodon?

A three-nucleotide sequence on tRNA that is complementary to a three-nucleotide codon on mRNA

Wobble pairing

Things that don’t normally pair up pair up

What are the three phases of translation?

Initiation, elongation, and termination

What is the start codon?

A-U-G

What are the three binding sites of ribosomes?

A, P, E

Polypeptide

When many amino acids link up

Epigenetic changes

When changes to the packaging of DNA alter the ability to access a gene

Operons

A cluster of genes that are under the control of a single promoter

What are the four major parts of the operon?

Structural genes, promoter genes, the operator, and the regulatory gene

Structural genes

They code for the enzymes needed in a chemical reaction

Promoter gene

The region where RNA polymerase binds to begin transcription

Operator

A region that controls whether transcription will occur

Regulatory gene

Codes for the represor

Repressor

Capable of attaching to the operator and blocking transcription

Post-transcriptional regulaton

Where the cell creates an RNA and decides that it shouldn’t be translated into a protein or when a cell has already created a protein but decides not to use it yet

RNAi 

silence gene expression by targeting and degrading specific mRNAs

Morphogenesis

The process in which the cell changes shape and organization many times

Homeotic genes

The early genes that turn cells into its future shape

Hox genes

A group of homeotic genes

Mutation

An error in the genetic code

How can mutations occur?

DNA can’t be repaired or DNA damage is repaired incorrectly

Base substitution

When a single nucleotide base is substituted for another

Nonsense mutations

Cause the original codon to become a stop codon

Missense mutations

Cause the original codon to be altered and produce a different amino acid

Silent mutations

When a codon that codes for the same amino acid is created (doesn’t change the corresponding protein sequence)

Insertions and deletions

Results in the gain or loss of DNA

Duplications

Can result in an extra copy of genes and are usually caused by unequal crossing-over

Inversions

Can result when changes occur in the orientation of chromosomal regions

Translocations

When two different chromosomes break and rejoin in a way that causes the DNA sequence to be lost, repeated, or interrupted

Transposons

Gene segments that can copy and paste themselves throughout the genome

Fission

How bacteria divide

Virus

Nonliving agent capable of infecting cells

What are the two main components of a virus?

A protein shell (capsid) and genetic material made of DNA or RNA

Host

The thing infected by a virus

What are the two replication cycles of bacteriophages?

The lytic cycle and the lysogenic cycle

Lyctic cycle

Immediately uses the host’s machinery replicate genetic material and create more capsid proteins

Transduction

The transfer of DNA between bacterial cells using a lysogenic virus

Enveloped viruses

Viruses with a lipid envelope

Reverse transcriptase

An enzyme that synthesizes DNA from an RNA template

Recombinant DNA

generated by combining DNA from multiple sources to create a unique DNA molecule that is not found in nature

Genetic engineering

The technology that produces new organisms or products by transferring genes between cells

Amplification

The process of creating many copies of genes

Transformation

The process of giving bacteria foreign DNA

Transfection

Putting a plasmid into a eukaryotic cell

Polymorphisms

Differences in DNA sequences