SCIC 202 (Life Sciences) Study Guide - Module 3, part 1 and 2- Fall 2024

Central Dogma

Chromosomes are composed of ______Chromatin__________, a combination of DNA and protein.

___________Hershey and Chase________________ are the researchers who showed that DNA is the genetic material

The monomers of DNA are __________Nucleotide______________. These monomers have three parts: __________Phosphate group_______________, ___________Nitrous Base____________, and _________Sugar_____________.

When they are linked together to build the polymers (called ___________Polynucleotide_____________), they form a _______________Sugar phosphate____________________backbone with _________bases__________off to the side. There are four types of nucleotides that make up a DNA strand: we call these nucleotides by the first initial of the base. The base pairing rules tell us that ___T____ always pairs with ___A___; and ___C__ always pairs with ___G___. This explains Chargoff’s rule (which states that the amount of __T_always equals the amount of A_; and the amount of C_ always equals G_).

The two researchers who discovered the base pairing rules and who also described DNA as a double helix were ________Watson___________and ________Crick_________. They based some of their work on the X-ray pictures made by _________Franklin and Wilkins___________.

When DNA is replicated, the double helix unwinds and this enzyme, _______DNA Polymerase_______, builds a new strand of DNA alongside each of the old strands, using the base pairing rules. This is Self-Conservative replication, since each new double helix consists of one old and one new strand of DNA.

According to Beadle and Tatum’s ____________one gene, one polypeptide________________hypothesis, DNA is the code for ___________Proteins___________.

In order to code for a protein, a gene must first be copied in the nucleus in the form of the other nucleic acid _______RNA________. This copying process is called _______Transcription__________. The difference in RNA and DNA is in the type of _________Sugar_________ in the molecule and in the base pairs: RNA does not have T; it has U instead, so DNA A is copied as mRNA U_. The enzyme that builds the new RNA strand is ___________RNA Polymerase__________.

mRNA leaves the nucleus and goes to the _________Ribosome__________ where the code is read in three letter “words” called ________Codon__________. Each codon codes for an ________Amino Acid____________, and the protein is built by hooking these together to form a polypeptide. This process (reading the code and building a protein) is __________Translation____________.

There are three types of RNA: ____________M(Messenger)________________RNA, which carries the genetic code from the nucleus to the ribosomes; _________R(Ribosomal)___________ RNA which is a part of the ribosome, and __________T(Transfer)_______________RNA, which brings the new amino acids into the ribosome when translation is happening.

** Be able to use the base pairing rules to produce a complimentary strand of DNA, transcribe it as RNA, and translate the RNA into protein on paper like we did in class.

Any change in the genetic code is a ________Mutation__________. These can occur when one base is put in the place of another, this is a base __________Substitution__________. It can also occur when a base is left out of the DNA molecule, this is a base __________Deletion____________, or when an extra one is put in, this a base ________Insertion_________.

State the Central Dogma of Biology:

DNA is transcribed to RNA translated to protein.

DNA Technology

Genetically Modified Organisms (GMOs)

Be able to define:

Genetically Modified Organism (GMO): have had DNA altered in a way that does not occur naturally

recombinant DNA: DNA that has had DNA from another source added to it

Plasmid: mall circles of DNA found in some bacteria

transgenic organism: contains DNA from another species (type of GMO)

Recombinant organisms (bacteria) are being used in the health care industry to produce: 1__________Thereputic Hormones_____________, 2_______________Treatment of Disease__________ and 3_____________Safer Vaccine production_____________.

Be able to list some examples of transgenic organisms and why they were produced (glofish, pest resistant crops, herbicide resistant crops, golden rice)

Goldfish: Make them glow

Pest resistant crops: kill bugs

Herbicide resistant crops: Kills weeds

Golden Rice: Vitamin A deficiency

List some possible problems with GMOs

-Do they harm non-target insects?

- Can they be transferred to wild plants?

- Do GMO plants affect other plants?

- Is there a danger of hidden allergen?

- Are they safe to eat?

Stem Cells

Be able to define:

Differentiated cells: specialized cells, perform a specific function

pluripotent stem cells: can give rise to specialized cells

unipotent stem cells: can only develop one cell type

Undifferentiated cells: not specialized

multipotent stem cells: can only develop into limited cell types

List the three general properties of stem cells:

1) Unspecialized

2) Pluripotent (Can give rise to specialized cells)

3) Capable of dividing and renewing themselves for long periods of time

List and define the three types of stem cells:

1) Embryotic = derived from early embryo

2) Adult = regenerate damaged organs and replenish dying organs; undifferentiated among specialized

3) Induced = differentiated adult are reprogrammed to an embryotic stem cell-like state

What embryonic stage of development is the source of human embryonic stem cells?

Human blastula

CRISPR/Cas9

CRISPR is used for gene editing. Gene editing is __________________Adding or repairing a gene____________________.

__________Gene Drive___________ allow for the modification of an entire species by inserting the CRISPR/Cas9 complex into the genome.

This human condition is being treated with gene editing using CRISPR___________Sickle cell_____________

The International Summit on Human Genome Editing recommended using gene editing only on (this type of cells) ________Somatic cells_________, which are not involved in reproduction.

PCR

PCR stands for __________________________ Polymerase Chain

Reaction__________________________________.

What does PCR do? _____________________Makes multiple copies of a DNA segment____________________________.

What are simple sequence repeats (SSRs)?____________________Same sequence repeated over and over_____________________________.

List the three circumstances we discussed in class or in your lab when PCR would be used :___________Paternity testing___________, ___________Crime scene_____________, and ____________Virus detection_________.

____________ Gel electrophoresis_______________is a technique use to separate bands of DNA based on their size

Evolution

Evolution (definition) is ___________________________Gradual change in a population over time__________________________________

List 5 categories of evidence to support the theory of evolution:

1.__________________Fossil record_______________________ 2.________________Biogeography___________________

3.__________________Comparative anatomy________________________ 4,_______________Comparative embryology____________________

5.__________________Molecular biology__________________________

Natural Selection (definition) is: individuals who can survive and reproduce in a particular environment pass their genes on to the next generation

Artificial selection is different from natural selection because: humans choose which individual reproduces

Polymorphism (definition) is: several variations are present for certain characteristics

List and describe the three ways natural selection acts on a polymorphic population:

1) Disruptive selection = population shifts to two extremes

2) Stabilizing selection = population shifts to intermediate form

3) Directional selection = shifts population to one extreme

This branch of evolutionary study combines the work of Darwin (on populations) and Mendel (genes and alleles) __________________________ Population genetics_______________________________________

All of the alleles for all of the genes in a population is that population’s ________Gene pool___________

If a population is begun by a few individuals, we may see reduced variation in the future due to the ___________ Founder effect___________________.

Any change in the allele frequency in a population is _____________Microevolution________________.

When individuals move into and out of populations, the change we see in allele frequency is due to __________Gene flow_______________.

Random change in a population is _____________Genetic drift_________________.

If a population is reduced severely in size, we call that a ________Bottleneck event____________event.

_____________Sexual selection________________occurs when one gender selects mates based on some characteristic. This can lead to a different appearance between males and females in the population (_____________sexual dimorphism__________________).

(Be able to recognize examples of : founder effect; gene flow; genetic drift; sexual selection; sexual dimorphism, natural selection, artificial selection, directional selection, diversifying selection, stabilizing selection)

Species and Speciation

We talked about 3 species concepts in class. The one that uses DNA similarities is the ___________ Phylogenetic ______________species concept. The __________ Morphological _____________species concept is based on physical similarities. The ____________ Biological ______________species concept uses fertility and says that all members of a species have the potential to breed and produce ______Fertile________ offspring.

A new species may be formed when a population is split for long periods of time by a geographic barrier (like a river or mountain range). This is _________ Allopatric_________ speciation.

Or a new species may be formed when a population splits without a geographic barrier, often due to polyploidy, sexual selection, or food preference. This is _________ Sympatric___________speciation.

The study of evolution that involves studying how organisms are formed is __________ Evo-devo_________. This involves studying the genes that control development (these are ________ Homeotic _____________genes) and often deals with retention of juvenile characteristics into the adult stage of life ( which is ___________ Pedomorphosis or neoteny________________).