UAB Bio Lab exam 3

Sickle Cell

Normal Blood

What is a karyotype?

A picture of all condensed chromosomes inside of a cell.

Why is the correct amount of genetic information important for cells?

Having too little or too much genetic information can be extremely problematic for cell and organism function.

What is the basic definition of biological sex in this course?

XX = female and XY = male, but more accurately referred to as assigned female at birth or assigned male at birth.

What are Barr bodies?

Condensed, inactive X chromosomes found in cells with more than one X chromosome, ensuring only one X remains active.

What is nondisjunction?

The failure of two chromosomes to properly separate during metaphase, occurring in Meiosis I or II.

What is Trisomy 21 commonly known as? Extra copy of chromosome 21

Down Syndrome-nondisjunction, distinct facial features, intellectual disability

What is Trisomy 18 commonly known as? Extra chromosome on 18

Edwards syndrome-delays- heart and organ defects, low birth weight, life-limiting

What is the first step in DNA isolation?

Homogenization, which involves blending strawberries with detergent to break apart cell membranes.

What is the purpose of deproteinization in DNA isolation?

To strip histones away from DNA by adding meat tenderizer.

What is the role of alcohol in DNA isolation?

To precipitate DNA, making it insoluble so it can be isolated.

What are the components of a nucleotide?

A phosphate group, a pentose sugar, and a nitrogenous base.

What is Chargaff's rule?

The content of adenine (A) equals thymine (T) and the content of guanine (G) equals cytosine (C).

What is the direction of DNA replication?

DNA polymerase reads in the 3' to 5' direction and synthesizes in the 5' to 3' direction.

What are Okazaki fragments?

Short segments of DNA synthesized on the lagging strand during DNA replication.

DNA polymerase I

removes the RNA primer and replaces it with DNA

What is the function of ligase in DNA replication?

To create covalent bonds between DNA fragments, acting as molecular glue.

What are the differences between DNA and RNA?

DNA: ATCG bases, double-stranded, contains deoxyribose sugar

RNA: AUCG bases, single-stranded, contains ribose sugar

What is transcription?

Process where DNA is copied into mRNA, which carries genetic instructions from the nucleus to the cytoplasm.

What are the three stages of transcription?

Initiation, elongation, and termination.

What is a codon?

A sequence of three nucleotides that codes for one amino acid.

What is the start codon and what does it code for?

AUG, which codes for methionine.

What are the stop codons?

UGA, UAG, UAA, which signal termination of translation.

Gene

coding for a particular trait

Allele

different variations of a gene

Gene pool

sum of genes within a population

Genotype

genetic make-up, alleles present on your chromosome

Homozygous

AA, aa having the same allele for a gene

Heterozygous

Aa having different alleles for a gene (dominant allele will be expressed)

Homozygous dominant

AA (having the dominant alleles)

Homozygous recessive

aa (having the recessive alleles, only expressed when they are homozygous)

Phenotype

the visual characteristics that are being expressed

Phenotypic frequency

individuals within population with a certain phenotype

Allelic frequency

the percentage of any specific allele in the gene pool

Genotypic frequency

the proportion of a given genotype within a population

Hardy-Weinberg Principle

Population is not changing/evolving

Gel electrophoresis

Technique to separate molecules based on charge

Sickle cell hemoglobin

Will have a different charge than normal hemoglobin protein

Genetic drift

Random changes in allele frequencies from one generation to the next, especially in small populations.

Founder effect

New population from a few individuals

Bottleneck effect

Drastic reduction in an existing population

Gene flow

The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes

Taxonomy

domain-> kingdom-> phylum/Division->Class->Order->Family->Genus->Species

Prokaryotic

Cells without a nucleus; simpler cell structure.

Archarea

Prokaryotes that live in extreme environments and have unique cell chemistry.

Bacteria

Prokaryotic organisms found everywhere; some helpful, some harmful.

DNA Polymerase

Enzyme that builds new DNA strands by adding nucleotides during replication.

Primase

Enzyme that makes short RNA primers to start DNA synthesis

Helicase

Enzyme that unwinds and separates DNA strands by breaking hydrogen bonds.

What is Triple X Syndrome?

• Cause: Female has an extra X chromosome from nondisjunction.

• Impacts: Usually normal development; may be taller, slight learning/language delays.

Klinefelter Syndrome (XXY)

• Cause: Male has an extra X chromosome due to nondisjunction.

• Impacts: Reduced testosterone, less body hair, possible infertility, some learning difficulties.

Turner Syndrome (X)

• Cause: Female missing one X chromosome (monosomy X).

• Impacts: Short stature, infertility, some physical/medical issues, normal intelligence.

Jacob’s Syndrome (XYY)

• Cause: Male has an extra Y chromosome from nondisjunction.

• Impacts: Often taller, normal fertility, possible mild learning or behavioral challenges.

In which direction is mRNA synthesized?

5' to 3' direction

What is the reading direction of DNA during mRNA synthesis?

3' to 5' direction

What are the base pairings for adenine in DNA?

Adenine (A) pairs with thymine (T)

What is the start codon for protein synthesis?

AUG (methionine)

What should be done when base pairs before the start codon do not match?

Ignore them and look for the AUG pair (TAC)

How are codons structured in mRNA?

Codons are letters of 3

What happens when a stop codon is reached during translation?

Detachment occurs and no amino acid is associated

What are the three sites in a ribosome where tRNA moves?

A (attach amino acid), P (polypeptide chain), E (exit)

DNA polymerase II

DNA repair 3-->5

DNA polymerase III

synthesizes new DNA only in the 5' to 3' direction, replication fork process

Mutation

Change in nucleotide sequence of DNA

allelic frequency equation

p + q = 1

genotypic frequency equation

p2 + 2pq + q2 = 1

p

dominant allele

q

recessive allele

p2

homozygous dominant

2pq

heterozygous

q2

homozygous recessive

Anticodons

Three letters on tRNA that match a codon mRNA

5 assumptions of Hardy-Weinberg

no mutations, random mating, large population size, no gene flow, no natural selection

Gram-positive bacteria

purple-thick cell wall

Gram-negative bacteria

pink

Barr bodies in males

0 (XY)

Barr bodies in females

1 (XX)

Purines

Adenine and Guanine

Pyrimidines

cytosine, thymine, uracil

Bacterial shapes

cocci, bacilli, spirilla

Archaea: Halophiles

salt loving

Archaea: Thermoacidophiles

Extreme temperature and acid loving

Bacteria: Kingdom Proteobacteria

Gram negative bacteria- e.coli, salmonella, and rhizobium

Bacteria: Kingdom Chlamydia

Sexually transmitted, survives only in animal cells, no peptidoglycan

Bacteria: Kingdom Spirochetes

uses flagella to spiral themselves through environment

Bacteria: Kingdom Cyanobacteria

Blue-green, photosynthetic