BIO GENETICS EXAM 1

Why are model organisms used in genetics?

Key to understanding genetics and used to understand universal biological genetic processes that can apply to humans or other life

What are some characteristics that most model organisms share?

Easy/fast growing, short lifecycle, many offspring, must relate to targeted study

What is some advantages of forward genetics?

Unbiased discovery, phenotype driven, and finding novel components

What is some disadvantages of forward genetics?

Time-consuming, intensive, difficult mapping, and redundancy/risk

What are some advantages of reverse genetics?

Targeted approach, study gene family, fast vaccine design, and bypasses random chance

What are some disadvantages of reverse genetics?

Requires prior knowledge, no visible effect, gene compensation, and lethality

What is forward genetics?

Naturally occurring mutations or intentional induced mutations to alter phenotypes in model organisms, determine the gene that created the new phenotype, and find the Observable phenotype, and work backwards to find the gene

What is reverse genetics?

DNA sequence for a particular gene of interest is more, but the function is not understood. (starts with an observable trait and works backwards to find your dream.)

What is gene knockout?

Renders the targeted gene non-functional in a model organism or cell

What is the molecular structure of DNA and RNA

Nucleotides in nucleosides

What is a nucleotide?

Made of three main parts. Phosphate group, sugar, and base (adenine)

What is a nucleoside

Part of a overall structure but focused on the sugar and base

Who is James Watson and Francis crick

Scientist who discovered the double helix structure of DNA in 1953 and who determined that the 3rd position is not as critical

What research did Rosalind Franklin and maurice Wilkins

Helped with the discovery of healing structure of DNA

What did Erwin chargaff discover

Amount of adenine and thymine in DNA are equal and amounts of guanine and cytosine are equal

What is deoxyribonucleic acid

Microscopic molecule inside cells that carry the complete genetic instructions for growth, development, and functioning of living organisms (DNA)

What is a nucleotide?

A molecular structure of DNA and RNA that can be broken down into three main groups (Phosphate group, sugar, and base)

What is a nucleoside triphosphate

A molecule made of nitrogenous base, a five carbon sugar, and a chain of three phosphate groups

What is a phophodiester

A connector between the three main groups of a nucleotide

What is a hydrogen bond compliment?

Specific matching of nitrogenous bases on opposite nucleic acid strands where hydrogen bond donors on one base pair with hydrogen bond acceptors as its partner

What is a inverse compliment?

Sequence obtained by reversing DNA or RNA sequence and replacing each nucleotide with its standard base pair

What is a eukaryotic chromosome?

Long linear, DNA molecules bound to histone proteins and housed inside a distinct cellular nucleus

What are some key structures of eukaryotic chromosomes?

• Linear structure

• Histone association

• Occurrence in sets

• Large

• Multiple origins of replication

• Centromeres

• Telomeres

What are the ordered cities of stats for packaging eukaryotic DNA into a cell

• DNA double helix

• Nucleosome

• Chromatin fiber

• Looped Domains

• Hetrochromatin

• Metaphase chromosome

  
  

How is the condensation of eukaryotic chromatin controlled

• protein complexes

• Histone modifications

• Phase separation that package DNA into compact structures

What is a Genome

An organisms complete set of genetic instructions, contains all the DNA needs to build, grow, and maintain living

What is a chromosome?

Thread, like structure made of protein in a single long molecule of DNA that carries genetic info from cell to cell

What is sister chrimatids

Two identical, halves of a single replicated chromosome joined together by a centromere

What is a karyotype

Complete set of chromosomes in a organism

What is a centromere

Central region that joins two sister chrimatides together

What is a telomere

A protective Structure made of DNA sequences and proteins found at the end of chromosomes

what is Chromatin

Complex mixture of DNA, RNA, and proteins that packages long DNA molecules into a compact dense shape to fit into the cell nucleus

What is a nucleosome

The basic repeating structural unit of chromatin

What is a histone

Specialized positive charge proteins that package long DNA molecules into compact structural units called nucleosomes inside the cell nucleus

What is heterocbromatin

Tightly packed DNA and protein found in the nucleus of eukaryotic cells that keeps certain genes off and protects the Genome

What is euchromatin

Loosely packed, lightly strained form of chromatin that contains active genes available for transcription

What is facultative

Genetic feature were processed as optional, conditional, or active only when specifically needed rather than all the time

What is constitutive hetrochromatin

Permanently condense, transcriptionally inactive region of DNA in all cells

What are the three main steps for DNA replication?

Initiation, elongation, and termination

True or false DNA replication is fundamentally the same in prokaryotic and eukaryotes

True

True or false each new double helix is half parent/half daughter strand

True

How is DNA replicated

A cell copies it’s genome before division, resulting in two identical double helix that each contain one original stand and one new strand

How does DNA polymerase synthesize a new DNA Chain

By reading a existing template strand and adding complementary nucleotides one by one in the 5 to 3 direction

How does DNA replication of a chromosome take place at the molecular level?

The double helix unwinds and each strand serves as a template to build a new partner

what type of phase does chromosomes duplicate In the cell cycle

S phase (DNA synthesis)

What is semiconservative replication?

The normal way DNA copies itself (New double helix contains one original parent strand, and one newly made daughter strand)

What is a conservative replication model

A hypothetical way of making DNA where the original double helix stays intact and builds a new separate double helix next to it

What is a dispersive replication model?

Disproven hypothesis of DNA replication where the parent double helix breaks into fragments each resulting in daughter molecules that has patchwork of old and new DNA segments along the strands

What is origin of replication?

Specific sequence of DNA where DNA duplication begins

What is a primer?

A short single stranded piece of nucleic acid that serves as a starting point of DNA synthesis

What is a semi discontinuous DNA replication

Process of synthesizing the lagging DNA strand in short separate segments rather than one continuous line

What is a lagging strand?

Template strand of DNA that is replicated discontinuously in short pieces during DNA copying

what is a Okazaki fragment

Short newly synthesis pieces of DNA formed on the lagging strand during replication

What is DNA polymerase 3

Main enzyme responsible for copying DNA during replication in bacteria

What is a primase

A enzyme that built short RNA pieces called primers

What is helicase

A enzyme that unwinds and separates double stranded nucleic acids into single strands

What is gyrase

A bacterial enzyme that relieves topological strain and introduces negative super coils into DNA during replication and transcription

What is ligase

A enzyme that joins two DNA or RNA molecules together by forming a chemical bond

What is DNA Polymerase 1

Prokaryotic enzyme that primarily removes RNA primers and replaces them with DNA during replication or repair

What is exonuclease

A enzyme that breaks down nucleic acids by removing nucleotides one at a time from the end of a chain

What is proof reading

Real time error correction process used by enzymes to detect, remove, and replace mismatched nucleotides during DNA replication

What are the three steps of polymerase chain reaction? (PCR)

Denaturalization, annealing, and extension

What happens during denature?

Separating DNA strands

What happens during annealing

Primer bind/attach

What happens during extension

DNA polymerase creates new DNA from 5 prime to 3 prime

How are primers designed in order to enable PCR?

Two primers (forward and reverse) that find opposite strands, blank the target sequence, and have their three prime ends pointing towards the region being amplified

What is PCR

Polymerase chain reaction, lab technique used to detect/amplify genetic material

What is denature?

To alter the natural structure of a protein or nucleic acid, causing it to lose its normal function

What is anneal

To allow complementary strands of DNA or RNA to pair and form a stable double stranded structure through hydrogen bonding

What is extension

The process where DNA polymerase adds nucleotides to the 3 prime end of a primer, synthesizing a new strand in the 5 to 3 direction

What is dNTP or deoxyribonucleoside triophosphate

The four main building blocks of DNA:

• deoxyribose sugar

• Nitrogenous base

• Three phosphate group

What is the central dogma

When genetic information flows only in one direction from DNA → RNA → protein

How is RNA chain synthesized

RNA is synthesized from a DNA template by the RNA polymerase

Where is RNA synthesis in bacteria/prokaryotes

Cytoplasm

Where is RNA synthesis in eukaryotes?

Nucleus

True or false DNA polymerase does not replicate the entire Genome

False

Why does RNA polymerase transcribe only part of the Genome

RNA polymerase is only responsible for expressing genes

What is transcription?

The process of duplicating a segment of DNA into RNA for gene expression

What is coding strand?

DNA strand that is not being used but has the same sequence as the RNA that is made

What is a template strand?

The strand of DNA that RNA polymerase reads to make RNA

What is a promoter?

A sequence of DNA which proteins bind to initiate transcription

What is RNA polymerase?

The enzyme that makes RNA from a DNA template that reads DNA 3 prime 5 prime

How is transcription initiated in bacteria

Sigma factor helps RNA polymerase find the promoter and begin transcription

How is transcription elongated in bacteria

RNA polymerase reads the template DNA 3 prime to 5 prime and builds RNA 5 prime to 3 prime

How is transcription terminated in bacteria

RNA polymerase reaches a terminator sequence, stops transcription, and releases the RNA

How does initiation occur in eukaryotes?

Transcription factors help RNA polymerase 2 bind the promoter

How does elongation occur in eukaryotes?

RNA polymerase 2 reads template DNA 3 prime to 5 prime and makes pre-mRNA 5 prime to 3 prime

How does termination occur in eukaryotes?

Transcription ends and the RNA is released

What occurs during the process in eukaryotes

Pre-mRNA gets a 5 prime cap, poly-a tail, and has introns removed and exons joined to produce a mature mRNA

What is transcription?

The process of duplicating a segment of DNA into RNA for the purpose of gene expression

What is a promoter?

A sequence of DNA which proteins bind to initiate transcription

What is -10/-30 sites

Important, bacterial promoter sequences recognized by the sigma factor before the transcription start site

What is a sigma factor?

Bacterial protein that helps RNA polymerase recognize and bind the promoter usually leaving After transcription begins

What is RNA polymerase?

Enzyme that reads template DNA 3 prime to 5 prime and builds RNA 5 prime to 3 prime

What is RNA polymerase holoenzyme?

Complete bacterial transcription complex: core RNA polymerase + sigma factor

What is stem loop termination sequence?

Bacterial termination signal where the newly made RNA forms a hairpin/stem loop causing RNA polymerase to stop and release the RNA

What is TATA sequence

Common eukaryotic promoter sequence that helps position transcription factors and RNA polymerase for transcription

What is general transcription factor?

Eukaryotic protein that helps RNA polymerized 2 find the promoter and initiate transcription

What is a enhancers?

DNA sequence that increase transcription when activator proteins bind To them (can be far away from the gene)

What are the three major steps of eukaryotic RNA processing?

• 5 prime capping

• RNA Splicing

• 3 prime polyadenylation

(Cap→splice→tail)