Biology 301 final exam

innate immunity (3)

• non-specific recognition of pathogens

• Does not involve antibody production - so it isnt a long lived response (no memory)

• Humorai and cell-mediated immunity

Complete Cascade

activation of plasma proteins

the macrophage (3)

• known as the “gig easters”

• slower than granulocytes when responding to invaders but are larger, live longer, and have more capabilities

• KEY role is alerting the rest of the immune system of invaders

where do macrophages start

start out in the white blood cells (monocytes) and once the monocytes leave the blood stream they turn into macrophages

The dendritic cells (4)

• “eater cells”

• devours intruders

• helps with the activation of the rest of the immune system

• capable of filtering the body fluids yo clear them of foreign organisms and particles

adaptive immunity (3)

• involves cells that produce antibodies (b cells)

• as well as the activation of cells that will attack the invading pathogens (cytotoxic T cells

• Recognition of specific antigens

Antigens (3)

• molecules that enter the body and trigger an immune response

• could be a foreign substance from the environment, such as chemicals, bacteria, viruses, or pollen

• could also be from within the body, as with bacterial toxins or tissue cells

T4 helper cells (2)

• major driving force and the main regulators of the immune defense

• primary task: activate B cells and killer T cells

helper t cell activation (2)

• helper t cells must be activated

• once activated by recognizing antigens in the antigen presentation, helper t cells start to divide and produce proteins that activate B and T cells as well as other immune cells

B or T cell Diversity (2)

* Each B or T cell recognizes ONE antigen
* this is due to the expression of a specific DNA sequence

what generates b and T cell diversity

generated by recombination at the DNA level of T cell and B cell receptors, only in that part of the genome coding for the T cell receptor an the B cell antibody genes

Rh factor (4)

• Rh antigen discovered by Rhesus Macaques

• Rh+ allele is dominant

• Rh- is recessive

• Pregnant moms who are Rh- can mount immune responses against the baby if it is Rh +

CAR T therapy

• Harvest T cells form Patient

• Genetically engineer anti tumor property (anti-CD19)

• Infused back into the patient where the T cell attack the cancer cell that express CD19

Is Hominid evolution straight line/ linear

No, it had many branch points and there were several different hominid species that lived at the same time.

Methods to determine the age of bone samples or other materials at an archeological site (4)

• carbon dating

• Molecular clock

• Aragon dating

• paleomagnetic dating

Carbon dating

there are different isotopes of Carbon (element labeled as C) and C14 is generated in the atmosphere at a predictable rate, and is incorporated into the food chain through plants and up the food chain. This C14 half-life is known, so by determining the ration of C14 to C13 in a sample, we can determine its approximate age.

limits to carbon dating (2)

• needs to be something that was once alive (wood, skulls, fabrics made from plant or animal products)

• can only go back about 80, 000 years, which is less time than when humans have evolved

molecular clock (3)

• Analyzing the DNA of different species, and determining how far apart they are on an evolutionary tree by examining the number of genetic differences between the two species.

• This is informed by knowing the typical mutation rates for DNA.

• Mainly useful for figuring out how long ago living species or populations shared a common ancestor, based on their DNA

Argon dating (2)

• Measures the breakdown of potassium to Argon40, alternatively, Argon40/Argon39ratios.

• Can be used to date rocks and minerals back several millions of years

Paleomagnetic dating

based on the frequency of reversals in the magnetic poles, and uses a timescale based on that.

primates (3)

• Date back to 65 million years ago

• Physical characteristics include: Forward facing eyes/front of face, color Vision, Hands and feet with nails instead of claws, able to grasp, Larger brain to body weight.

• Include Monkeys and Apes, humans are Great Apes and there were many hominid species that came before us

did humans descend from apes?

We did not descend from Gorillas, Chimpanzees, or Bonobos, but we had common ancestors and branched off. The Last common ancestor between chimps and humans was about 6-8 million year ago

Hominid species-Evolved in Africa aka “out of Africa” model. (3)

• 4 million years ago-Homo Australopithecus (Lucy Skeleton)- Short with small heads, walked upright, branched into “Homo” species and “Paranthroupus” species. The Paranthroupus branch died out, we come from the Homo lineage.

• -2.5 million years ago Homo Habilis, used tools that we have fond as artifacts

• -2 million years ago, Homo erctus, taller than H Habilis, larger brain, and had more sophisticated tool use, used fire, migrated out of Africa 2 million years ago.

neanderthal (2)

• 1st Neanderthal species lived around 600,000 to 300,000 years ago

• DID NOT live in Africa Shorter limbs, barrel chest, flat forehead, small chin large nose, large brain,

end of neanderthals’ (2)

• Died out around the same time as humans arrived in Europe and Asia.

• Were both alive at the same time for about 30,000 years, and there is evidence of interbreeding between early humans and Neanderthals.

homo sapiens evolution (2)

• Homo sapiens (aka, humans), evolved around 200,000 to 100,000 years ago

• Small groups migrated out of Africa 60,000 years ago

genetic diversity in Africa (2)

• Human population that are in Africa have the most amount of genetic diversity.

• As groups left Africa, they only carried with them a proportion of the alleles,

Neanderthal DNA vs Human

While Neanderthals are 99.5% sequence similar to ours, there are enough difference to tell apart human DNA from Neanderthal DNA, and to fine Neanderthal DNA makes up 1 to 4% of DNA from European and Asian descendants

was neanderthal DNA sequence observed in the genomes of people from Africa

no

Population Genetics

The study of the distributions and changes of allele frequency in a population, as the population is subject to the four main evolutionary processes:

the four main evolutionary processes (4)

• natural selection,

• genetic drift,

• mutation

• and gene flow

Natural Selection (2)

• natural processes that select for the reproduction and survival of a individuals or groups that are best adjusted to their environment.

• Evolution of species is based upon this concept

natural selection and adaptation (2)

• Species or individuals of a species that can adapt to the environment can reproduce and pass down their genes to other generations.

• Meaning that a characteristic can change in a population over time as the genes allowing for this adaptation are preferably based on

is natural selection random?

no

genetic drift (3)

• Changes in gene distribution based on random sampling.

• When a smaller group of individuals leaves a larger group, they are more susceptible to genetic drift because they carry a smaller proportion of all of the total possible alleles.

• Over time this can make the original population and the group that was separated have different trait frequencies based on different allele frequencies:

Situations that lead to Genetic drift (2)

• Bottleneck effect

• The Founder effect

founder effect (4)

• A subgroup of individuals go to a new environment and start a subgroup of the population.

• The alleles that the founder group carried with them are represented in the offspring.

• Alleles that might have been rare/low frequency in the population that these founders came from may be enriched/have higher allele frequency in the new population.

• Rare alleles are also more likely to disappear in that smaller population. Can disappear by chance in subsequent generations

Bottleneck effect (2)

• a natural disaster or disease reduces population size and a smaller group of individuals are left to pass on their alleles.

• This can lead to a common allele become less frequent because so many individuals with those alleles died by chance

is genetic drift random?

yes

gene flow (3)

• Transfer of alleles from one population to another, often due to migration.

• If two groups from two regions come into contact with each other and successfully reproduce, the offspring will have alleles from both groups.

• This introduces new alleles into a population.

Mutations (2)

• can lead to new alleles in the population.

• If that mutation leads to an advantage for survival or reproduction, it may become more common in that population

Example of a mutation becoming common (2)

• Sickle Cell mutation provides a survival advantage under the selection pressure of Malaria (you are more likely to survive if you have only 1 copy of the sickle cell anemia allele).

• Therefore, this allele is more common in areas of Africa where there is a lot of Malaria.

the founder effect on rare diseases

* rare disease alleles becoming more frequent in certain populations.

founders effect and huntingtin disease

Huntington Disease in the Maracaibo region of Venezuela Nancy Wexler identified the gene for HD by studying individuals from Maracaibo and tracing the inheritance of alleles in a large pedigree of families that had HD from Maracaibo.

Huntington Disease

HD is a autosomal dominant disease (1 copy of the disease allele will give you the disease). It is caused by an expansion of a tri-nucleotide repeat that causes one amino acid to be repeated too many times. This causes the huntingtin protein to misfold and become toxic to the neuron.

Founder effect in Amish/Menonites (9)

• 100 founders, now about 90K people:

• Ellis-van Creveld syndrome

  • – Short stature, polydactyly, heart and dental abnormalities –

  • EVC gene regulates an important developmental gene (Shh)

• Glutaric acidemia

• Diet restrictions can prevent loss of function

• Cohen Syndrome

• Epilepsy

• Maple Syrup Urine Disease

founder effect in Louisiana

• USH1C (also known as Harmonin) 216A mutation that causes Usher syndrome (higher proportion of people carry this rare allele).

• HexA gene mutations that cause Tay Sachs disease

• Hereditary Spastic Paraplegia (French Settlement Disease).