Bio 111 – Final Exam Study Guide Flashcards

Flashcards with vocabulary and definitions from Bio 111 Final Exam Study Guide.

Gregor Mendel

Austrian monk who discovered the basic fundamentals of genetics by studying peas.

Blending Theory of Inheritance

The theory that offspring are intermediates of parents, disproven by Mendel's experiments.

Characteristic and traits that were easily measured AND they were on separate chromosomes- no linked chromosomes

1. Why was the pea plant such a useful study organism for early work on genetics?

Particulate Theory of Inheritance

The theory that alleles are located at specific loci and are transmitted separately to the next generation.

Allele

A form of a gene. Example: eye color - green vs. brown.

Locus

The location of a gene on a chromosome.

Marfan Syndrome

An autosomal (dominant) genetic disorder caused by a defect in elastic protein.

Huntington Disease

An autosomal dominant disorder causing degeneration of brain cells.

Phenylketonuria (PKU)

An autosomal recessive disorder preventing normal metabolism of phenylalanine.

Cystic Fibrosis

An autosomal recessive disorder caused by a faulty chloride ion transporter.

Hemophilia

A sex-linked recessive disorder in which the blood is slow to clot.

Red-Green Colorblindness

A sex-linked recessive disorder causing loss of either red or green sensitive cones.

The defective allele (recessive) is carried on the X chromosome. Females can be carriers, males cannot. Males only need 1 recessive allele to get the disease.

How does muscular dystrophy work?

Incomplete Dominance

“Blending” of alleles/phenotypes (1 allele incompletely masks the effect of another).

Complete Dominance

One allele completely masks the effects of another allele.

One allele dominant

incomplete dominance, codominance

One locus per trait

multiple loci per trait (2 loci for chicken color)

Affect phenotype a lot - color in bunnies (determine whether a trait is expressed or not)

To what degree can the environment affect the phenotype?

Genetic Linkage

Traits that are inherited together because their genes are on the same chromosome.

Genetic Recombination (Crossing Over)

Can give you new gamete combinations when otherwise impossible; plays a role in genetic linkage.

-Can give you new gamete combinations when otherwise impossible

What role does genetic recombination (crossing over) play in genetic linkage? 

-Add up all offspring then add up recombinants and divide recombinants by total offspring

-Genetic distance: location of 1 locus - location of another locus

How do we calculate recombination frequency?  How can we use those numbers to construct genetic maps of chromosomes?

Sex Chromosome

Chromosome that codes for biological sex.

Autosome

Any chromosome that doesn’t code for biological sex.

-They only have 1 x chromosome so they only need 1 “bad” allele

Why is it that males are so much more likely to express an X-linked trait?

-Colorblindness (overlap of red and green wavelengths in cones)

-Hemophilia - incompletely formed clotting factors

What are some examples of human X-linked traits?  How do they work?

-20 amino acids in proteins - bigger alphabet

-4 nitrogenous bases in DNA - smaller alphabet

Why is it that early researchers were so skeptical that DNA, and not protein, could carry our genetic information?  Looking ahead to chapter 10, what is the solution to this problem?

Hershey and Chase

Scientists who used bacteriophages and radioactive labels to prove that DNA is injected into cells, not protein.

Frederick Griffith

Showed “transformation” in mice. Transformation occurred when heat killed virulent strains were introduced to non-virulent R strains

Avery, Macleod and McCarty

Showed the transforming agent was DNA by building off of Griffith's experiment and removing protein from the virulent strains

Erwin Chargaff

Quantified the amounts of different nucleotides and established complementary base pairing.

Rosalind Franklin

Took an X-ray crystallography image of DNA that suggested a helical structure.

James Watson and Francis Crick

Constructed a physical model of DNA and received a Nobel Prize in 1962.

Friedrich Mieschner

Isolated nuclei from white blood cells and precipitated out DNA. First person to see DNA under a microscope

Alfred Hershey and Martha Chase

Used bacteriophage T2 and Phosphorous and Sulfur isotopes that that provided important evidence that DNA and not protein is the genetic material

Matthew Meselson and Franklin Stahl

Used light and heavy Nitrogen isotopes to label genetic information in E. coli. Determined that DNA was replicated semiconservatively

• 5’ end attached to a Phosphate group

• 3’ end attached to hydroxyl group

Be able to describe the structure of DNA in detail: the bases, how they are assembled into nucleotides, and how the nucleotides are assembled into the double-stranded DNA molecule.  What do we mean by a 3’ end or a 5’ end?

DNA unzips by helicase to provide a template strand DNA polymerase can build a new strand on the template from the 5’ to 3’ direction (one strand is always older)

How does the fact that DNA replication is semiconservative relate to the mechanism of DNA replication that we studied in class (helicase, DNA polymerase III, etc)?

Initiation

 Helicase unzips, Primase adds an RNA primer to an origen sequence - this provides an open 3’ end

Elongation

• Nucleotides are added from 5’ to 3’ (linked together) against their complementary template by DNA polymerase (mostly III, Polymerase I used for Okazaki fragments)

• Ligase glues together any gaps left by primers or okazaki fragments

Termination

• end sequence, and an overlapping telomere is left on the chromosome and telomerase adds nucleotides back so the chromosome doesn’t shorten

*DNA strands are antiparallel

-Leading strand replicates continuously from 5’ - 3’ direction

-Lagging strand must use okazaki fragments which add nucleotides in the opposite direction of the replication fork so they can be added in 5’ to 3’ direction (leap frogging)

-Enzymes

-Leading strand - DNA polymerase (start with Primase)

-Lagging strand - primase adds a primer, DNA polymerase adds nucleotides, ligase to glue gaps left from primers together

Why must DNA replication occur differently on the leading vs. the lagging strand?  How does that occur?  Identify the enzymes involved.

-Overhang left at the end of the chromosome with an open 5’ end. DNA Polymerase can’t replace the nucleotides because it needs an open 3’ end. Primase facilitates the addition of an RNA template to provide an open 3’ end for polymerase to add nucleotides

What is the specific problem that telomerase solves, and how does it solve it?

-DNA polymerase catches most of the mistakes replaces mismatched nucleotides

-Mismatch repair proteins catch the ones that DNA polymerase misses

-This happens rarely

We did not discuss this in class, but you should be comfortable with the concept of DNA proofreading and mismatch repair as mechanisms to prevent mutations.  See the last slide from the lecture notes, as well as your textbook.

• change the amino acid sequence, that changes the protein function, and that causes the disease

• What violates it? Exon shuffling - exons can be put together in many different ways - so you can get multiple proteins from 1 gene

Explain why diseases like phenylketonuria and alkaptonuria support the “one gene, one  polypeptide” hypothesis.

The pathway would work until you get to the faulty enzyme (if it is near the end). If mutated at the beginning - the pathway wouldn’t work at all (it would cause a chain reaction)

How might a mutation in a gene that encodes an enzyme that appears near the end of a long metabolic pathway be different from one in an enzyme that appears near the beginning of a pathway.  Relate this to activities like the first question in our worksheet for this chapter.

DNA - RNA -PROTEIN

What are the three principle steps through which genetic information passes during gene expression

• DNA is 2 stranded double helix.  RNA is single stranded

• DNA has thymine.  RNA has Uracil

• DNA has deoxyribose sugar.  RNA has ribose sugar

• DNA is much larger than RNA

What are the differences between DNA and RNA (a.k.a. Central Dogma)?

-Introns are removed and exons are pieced together by spliceosomes made of snurps

-Methyl G cap, and poly A tail

1. What happens to a pre-mRNA in order to process it into a mature mRNA transcript?

• mRNA- messenger RNA - Linear and single-stranded

• tRNA- transfer RNA, secondary structure that folds back on itself 

• rRNA- ribosomal RNA - RNA and proteins that make up ribosomes

1. Describe the differences in structure and function between mRNA, tRNA, and rRNA.

-To disassemble the complex, otherwise proteins would go on forever

Why is it that stop codons bring in a release factor and not a tRNA?

Helicase

An enzyme that unzips DNA.

Primase

Adds an RNA primer to an origen sequence- this provides an open 3’ end.

DNA Polymerase

An enzyme that adds nucleotides from 5’ to 3’ (linked together) against their complementary template.

Ligase

An enzyme that glues together any gaps left by primers or Okazaki fragments.

Telomerase

An enzyme that adds nucleotides back so the chromosome doesn’t shorten.

Point Mutation

Mutation affecting only one or very few nucleotides in a gene sequence.

Silent Mutation

One of the nucleotides is changed, but the same amino acid is coded for.

Nonsense Mutation

One of nucleotides changes at the beginning therefore no protein made.

Missense Mutation

Most of the protein is built, but the amino acids change due to a mutation and the protein misfolds.

Frameshift Mutation

Nucleotides added or deleted so the entire sequence is shifted (all incorrect amino acids following the mutation).

Williams Syndrome

Deletion at end of chromosome 7 that often leads to excellent skills like verbal & music, cheerfulness but reduced academic performance.

Cri du chat Syndrome

Deletion in chromosome 5. Infants cry sounds like cat, larynx & nervous system problems. Severe cognitive, speech, motor delays.

Alagille Syndrome

Translocation between chromosomes 2 & 20. Symptoms can be extremely mild, but may include: Severe heart & liver disease. Chronic itching, jaundice, broad forehead.

Trisomy 21/Down Syndrome

Homologous chromosome 21 gets stuck together during meiosis. Child receives 3 chromosome 21’s instead of 2. Intellectual disabilities.

Klinefelter syndrome

X chromosomes get stuck together during meiosis. Genotype XXY. Enlarged breasts, minimal facial & body hair, Small penis & testicles, Sterile.

Jacobs syndrome

Y chromosomes get stuck together during meiosis. Genotype XYY. Taller than average, Increased risk of learning disabilities. May include antisocial or behavioral problems.

Turner Syndrome

Do not develop menstrual periods or breasts without hormone treatment, unable to have children without reproductive technology. Higher incidence of heart effects, diabetes, & hypothyroidism.

Epithelia Tissue

One major class of tissues. Example: stratified squamous epi - skin

Connective Tissue

One major class of tissues. Example: blood

Nervous Tissue

One major class of tissues. Example: neuron

Muscle Tissue

One major class of tissues. Example: cardiac= heart

Cardiovascular System

Organ system that circulates blood throughout the body.

Respiratory System

Organ system that removes CO2 from blood and adds O2 to tissues.

Nervous System

Organ system that carries electrical impulses to direct intentional and automatic actions of the body.

Integumentary System

Organ system that is the barrier of protection between the inside of the body and the external environment.

Musculoskeletal System

Organ system that provides structure and allows motion in the body by contracting.

Digestive System

Organ system that extracts nutrients from food and excretes waste products.

Endocrine System

Organ system that produces hormones to direct activities of other organs.

Urinary System

Organ system that filters waste products from the blood and maintains body’s water balance.

Reproductive System

Organ system that produces sperm in the male and eggs in the female. Also, structures in this system allow the organism to carry and give birth to offspring.

Lymphatic System

Organ system for the immune response.

• There is a error signal, a setpoint, and feedback information

• Example: Body temp regulation. Hypothalamus (control center) detects a change in blood temperature (error signal), this information is integrated in the hypothalamus and sent to effectors (muscles if organism is cold - shivering warm it up, sweat glands if the organism is hot)

• Why is it a negative feedback loop? It always returns to the set point

• Positive feedback? When a response is amplified.

Describe the different elements of a feedback loop, and how these feedback loops allow us to maintain homeostasis.  Be prepared to use these elements when provided with a narrative describing a specific example

Anticipates internal changes and changes the set point.

What is feedforward information?

Ectotherm

An animal that is cold blooded, where their body temperature is directly influenced by the environment.

Endotherm

An animal that is warm blooded, where their body temperature stays relatively constant.

Circadian Rhythm

Day-to-day cycles; innate light dark cycles are not exactly 24 hours.

Suprachiasmatic Nuclei (SCN)

Structure in the brain which is responsible for maintaining the 'master' circadian clock.

• In the cold - Rounder bodies, shorter limbs, fat insulation, smaller ears, in feet countercurrent heat exchange in their capillaries (warm blood interacting with cold blood and the heat transfer between capillaries keeps it above freezing)

• In the heat - longer legs, bigger ears, little insulation, other mechanisms of heat loss - like sweating, panting or gaping

• When comparing relatively small mammals, such as mice and shrews, to large mammals, such as elephants and horses, the mice and shrews have higher basal metabolic rates.

What specific adaptations do many endotherms have that allow them to maintain their body temperatures? 

-Heat gain + heat loss = temp change unless heat gain is equal to heat loss

-Conduction - heat transfer from touching a surface

-Convection - heat transfer in a medium (water or wind)

-Radiation - sunlight

-Evaporation - sweating

Be comfortable with the different elements of the heat budget equation.  Discuss each, and how each might vary under different conditions (e.g. a hot sunny day vs. a cold windy day vs. a hot windy day vs. a cold sunny day).

These are day-to-day cycles. We talked about how innate light dark cycles are not exactly 24 hours. Light is used to entrain the animal’s cycle each day. We looked at the example of the running activity of mice on exercise wheels where the measured the activity in a regular 12 hour light, 12 hour dark cycle, complete darkness for days, and only 15 minutes 2 x a day.

11. How do circadian rhythms work?

Melatonin

13. What specific hormone is affected by late night studying?