Biology Exam #2 (Ch. 6-11)

15. What is adaptive radiation? Be able to recognize a situation where adaptive radiation has occurred.

*Adaptive Radiation* - populations of one "founder" species become geographically isolated - each population experiences different selective pressures - multiple speciation events originating from a single species - occurs on islands to create huge speciation events - birds come from the mainland and spread out on the islands ex: Finches

14. What is the difference between allopatric speciation and sympatric speciation?

*Allopatric Speciation* - the formation of new species through geographic separation - no gene flow - it is reinforced by reproductive isolation - courtship rituals (species-specific): dances, coloration (ex: breeding plumage), and build structures *Sympatric Speciation* - the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region

9. If a genetic disorder is autosomal recessive, how many recessive alleles must an individual inherit in order to express the disorder?

*Autosomal*: not X-linked (so just normal BB or bb or Bb not XBXb or XBXB or XbXb or XbY or XBY - the individual must have two recessive alleles

3. What does it mean when an allele is dominant? What about recessive?

*Dominant* - dominant alleles hide the recessive alleles - and organism needs only one dominant allele to express the dominant phenotype *Recessive* - in order to express the recessive phenotype, the organism must have two recessive alleles

10. What is gene flow? How is it different from genetic drift? a. Be able to recognize examples of gene flow

*Gene Flow* - movement of individuals into or out of a population -> immigration (adds alleles) -> emigration (removes alleles) It is different from genetic drift because genetic drift is when a whole population is formed while gene flow is just when organisms go in or out of a population (do not start a new population)

2. Define genotype and phenotype. Explain how they are different

*Genotype* - combination of alleles in each plant - underlying genetic makeup, consisting of both physically visible and non-expressed alleles, of an organism *Phenotype* - observable traits expressed by an organism - physical expression of the genotype - the appearance of the organism

12. What is a homologous structure? a. Are the wings of birds and the wings of bees homologous structures? Why or why not? b. Are the forearms of chimpanzees and the forelimb of dogs homologous structures? Why or why not?

*Homologous Structure* - organs or skeletal elements of animal and organisms that, by virtue of their similarity, suggest their connection to a common ancestor - these structures do not have to look exactly the same or have the same function a. The wings of bird and the wings of bees are *NOT* homologous structures, they are analogous structures because even though they share a similar look and function, they do not share a common ancestor b. The forearms of chimpanzees and the forelimbs of dogs are homologous structures because they share a common ancestor even though they do not have a similar look or function

6. Explain how the following vary from the typical dominant/recessive relationship of alleles: a. Incomplete Dominance b. Codominance

*Incomplete Dominance* - when the phenotype of the heterozygote os a blend of the dominant and recessive phenotypes ex: pink and white spotted roses or the pink snapdragons *Codominance* - when both alleles are equally and fully expressed in the heterozygote - neither allele is dominant over the other ex: blood types (AB)

8. Describe the difference between Interphase and the Mitotic phase of the cell cycle

*Interphase* - majority of the cell - DNA replication - preparation for cell *Mitotic Phase* - two cells from one - pull DNA to 2 sides and cleaves into 2 - nucleus and cytoplasm

5. What is microevolution? Provide and example of microevolution?

- changes that occur in the characteristics of a population - within one species - can occur "quickly" - results in changes of alleles frequencies ex: bacteria becoming resistant to the antibiotics used to fight the bacteria

Homologous Chromosomes

- chromosomes of the same morphology with genes in the same location; diploid organisms have pairs of homologous chromosomes (homologs), with each homolog derived from a different parent

Chromosome

- composed of tightly coiled DNA wrapped around packaging proteins called "histones" - chromosomes are easier to move during cell reproduction than unwound DNA - each chromosome has two sister chromatids

Cytokinesis

- division of the cytoplasm following mitosis that forms two daughter cells

15. Identify two reasons why genetically modified organisms are produced despite their controversial reputation

1. Medical Purposes - transgenic goats make anti-clotting proteins 2. Increased crop yields - Bt crops 3. Eliminate disease - GM mosquitoes

2. What are the four types of nitrogenous bases that are found in DNA? a. If one strand of DNA has the following sequence, be able to identify what the complimentary sequence would be: TAACGTTC

DNA: CTGA a. TAACGTTC=CTTGCAAG

11. Explain how each of the following provided evidence in support of common descent (evolution). ALSO provide an example that we discussed in class for each a. Fossils b. Anatomical similarity (homologous structures) c. Geographic distribution d. DNA similarity

I will do these are separate cards so it does not get confusing

12. Understand how to solve a pedigree. In other words, be able to look at the pattern of affected individuals in the pedigree, determine the mode of inheritance, and assign genotypes to the relevant individuals in the pedigree

I would look back to the examples we did in class

1. What are the two basic types of cell reproduction

Mitosis and Meiosis

2. Be able to describe the process of natural selection in your own words (and not using the phrase "survival of the fittest")

Natural selection is a mechanism of evolution where traits are inherited, more offspring are produced than the environment can support, and there is competition for limited resources. This results in some offspring surviving and being able to reproduce better than others in a particular environment

5. Do all alleles for all genes exhibit complete dominant/recessive relationship?

No because there are things like incomplete dominance and codominance that can occur

1. What type of organic molecules are DNA and RNA? (Carbohydrate, Lipid, Protein, or Nucleic Acid?)

Nucleic Acid

3. What are the four types of nitrogenous bases that are found in RNA? a. If a strand of DNA has the following sequence, be able to identify what the complimentary sequence of RNA would be: TAACGTTC

RNA: CUGA a. TAACGTTC=UAACGUUC - note: RNA is usually a temporary substance so it uses U instead of T because U is easier to break down

4. According to the principle of natural selection, what is responsible for selecting the most successful individuals in a population: the environment or the organisms themselves?

The environment

9. List the phases of meiosis I and meiosis II in the order in which they occur. Describe what happens during each phase

The following cards will have the list and description since it is too much to put on one card alone

1. What does the theory of evolution state?

The theory of evolution states that living things present on earth today are the diverse descendants of a single common ancestor

8. Is the ribosome involved in transcription or translation?

Translation

2. Define the following: chromosome, sister chromatid, homologous chromosomes, diploid, haploid, cytokinesis

the terms and definitions will be on the next cards

6. Explain the difference between microevolution and macroevolution. a. Following the introduction of a new pesticide, a population of tomato hornworms evolves resistance to the pesticide over the course of 50 generations. Is this an example of microevolution or macroevolution? b. Birds and crocodiles share a common ancestor with dinosaurs. Is this an example of microevolution or macroevolution?

*Microevolution* - changes that occur in the characteristics of a population - within one species - can occur "quickly" - results in changes of alleles frequencies *Macroevolution* - the changes that give rise to new species - takes place over long periods of time - a product of many microevolutionary events a. microevolution b. macroevolution

7. What is a mutation? How are mutations the source of all genetic variation?

*Mutation* - a heritable change in the DNA sequence of a gene: new alleles - new alleles may be: selected against; favored by selection; neutral Mutations are the source of all genetic variation because mutations cause the variation which can then help the organism and lead to natural selection or harm the organism and the organism will not survive long enough to reproduce and pass that mutation on so the mutation does not last

Meiosis I

*Prophase I* - nuclear envelope disintegrates - chromosomes condense - homologous chromosomes pair up and form tetrads - crossing over occurs *Metaphase I* - tetrads line up along the metaphase plate *Anaphase I* - homologous pairs split, one chromosome goes to each pole - cell elongates *Telophase I* - chromosome uncoil - nuclear envelope reforms - cytokinesis occurs -> each daughter cell has one duplicated chromosomes from each homologous pair

Meiosis II

*Prophase II* - nuclear envelope breaks down and spindle apparatus forms *Metaphase II* - chromosomes line up on the equator *Anaphase II* - the sister chromatids are then separated *Telophase II* - then in cytokinesis, the two cells divide, resulting in 4 haploid cells **just a little note, I got this description of what happens in each stage from the Internet since he did not explain it on the slides so I apologize if it is missing a few things

6. List the phases of mitosis in the order in which they occur. Describe what happens during each phase

*Prophase*: - nuclear envelope disintegrates - chromosomes condense *Metaphase*: - chromosomes line up along metaphase plate *Anaphase*: - sister chromatids split and move towards opposite poles - cell elongates *Telophase*: - nuclei reform - chromosomes uncoil - cytokinesis also occurs: each daughter cell has 2 of each type of chromosome

7. What is a Punnett Square and why do we use them?

*Punnett Squares* - parents' sex cells go on the top and left side of square - offspring genotypes resulting from each "cross" go in the middle - we use them for the prediction of the percentages of phenotypes in the offspring of a cross from known genotypes - can be used to determine a missing genotype based on the other genotypes involved in a cross

14. Provide an example of a commonly used cloned product

*RBBG dairy products* - recombinant Bovine Growth Hormone is injected into cows to increase their milk yields by 20% *Insulin & Human Growth Hormone (HGH)* - produced by recombinant (transgenic) bacteria in large vats

13. What is speciation? What is a species?

*Speciation* - the evolution of a new species (or multiple new species) from an ancestral species *Species* - a group of individuals that are capable of interbreeding and producing fertile offspring - looks have nothing to do with species (can look almost identical and not interbreed- different species)

7. Distinguish between transcription and translation

*Transcription* - making an RNA transcript using DNA as a template *Translation* - protein synthesis - making a protein using mRNA as a template

9. Distinguish between the jobs of mRNA, rRNA, and tRNA

*mRNA* - messenger RNA - carries the genetic information copied from DNA in the form of a series of three-base code words *rRNA* - ribosomal RNA - makes up the ribosome *tRNA* - transfer RNA - reads the mRNA and brings in amino acids

10. What is a codon?

- 3 letter sequence of ribonucleotides on the mRNA - 3 -> code for one of the 20 amino acids

10. When a cell undergoes meiosis, how many daughter cells are produced? (at the end of meiosis II)? How many chromatids does each chromosomes have? Are the daughter cells produced by meiosis identical to the parent cell? Why or why not?

- 4 daughter cells - one chromatid in chromosomes - not identical because of crossing over

4. Be able to recognize an example of semiconservative replication. Foe example, if I were to provided you with the following two illustrations, would you be able to identify which one correctly describes DNA replication? (Grey= original or template strand; black= new strand)

- I cannot put the picture on quizlet so you will have to look at your study guide (I apologize) - copying of the genes - every time they split, one set is always from the original gene DNA replication is a semiconservative process because when a new double-stranded DNA molecule is formed: - one strand will be from the original template molecule - one strand will be newly synthesized

5. What is the role of DNA polymerase?

- adds nucleotides one-by-one to the growing DNA chain that is complementary to the template strand

Sister Chromatids

- are composed of identical strands of DNA - are formed when the DNA is copied (duplicated

Haploid

- cell, nucleus, or organism containing one set of chromosomes (n) - when cell has only one set of chromosomes or half the diploid number - do not have homologs pairs - only cells that are haploid are sperm and eggs (gametes)

Diploid

- cell, nucleus, or organism containing two sets of chromosomes (2n) - when cell has 2 of each type of chromosome (one from mom, one from dad) - 2n: two copies of that chromosome - diploid cells have chromosomes in homologs pairs

9. What is genetic drift? How are population bottlenecks and founder effects examples of genetic drift? How can these result in microevolution a. be able to recognize examples of genetic drift

- genetic drift is a change in the gene pool of a *small* population due to chance - bottleneck effect: only leaves a few organisms so the special alleles normally do not make it through - founder effect: small portion of organisms from a population separate and become founders of a new population with only the alleles that they brought with them These are examples of genetic drift because both the bottleneck and founder deal with small populations that resulted due a chance event. These can result in microevolution because the genes of the organisms in the "new" population are dependent upon the genes that the organisms already have so if this population is put in another place where one gene helps them survive more than other, then those organisms with that gene are going to survive and reproduce and pass on that gene

c. Geographical Distribution (Biogeography)

- historic continental movements can explain broad distribution of related groups - island species often resemble nearby mainland species; ex: marine iguana - related species exhibit similar geographic distributions - convergent evolution-> similar environment shapes organisms to look similar - despite superficial similarities, these mammals most closely resemble other mammals on their own continents

6. What is the role of RNA polymerase?

- it is the main transcription enzyme - it binds to a promoter sequence near the beginning of a gene (directly or through helper proteins) - it uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule

3. Why is genetic variation so important for natural selection?

- natural selection can only happen with the traits that are already there - with genetic variation, individuals can still survive - if there is no variation then natural selection will not happen

b. Anatomical Similarity (Homologous Structures)

- one bone, two bones, little bones, digits -> same pattern in humans as well as fish ancestors -> humorous, radius, ulna, distal elements: small variations in them; not all the same look and function but come from common ancestor - Homologous structures: come from common ancestor

11. What is the purpose of meiosis? That is, when, why, and where would meiosis occur in the body?

- produce gametes for sexual reproduction and to reduce the chromosome number - meiosis occurs in the sex cells, so the sperm and egg cells in the human body

d. Molecular Biology (DNA similarities)

- similarities between the eyes of a mouse and other animals - humans and chimps-> 98% similar genetically not through the proteins

a. Fossils

- the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock - since the remains are preserved, scientists can see the similarities in their bone structure to other organisms that are living and have also been found on fossils (Please let me know if you have anything to add to this because I did not get notes on this in class)

5. What is the purpose of mitosis? That is, when, where, and why would mitosis occur in the body?

- to make two cells from one cell

7. When a cell undergoes mitosis, how many daughter cells are produced? How many chromatids does each chromosome have? Are the daughter cells produced by mitosis identical to the parent cell? Why or why not?

- two daughter cells are produced - two chromatids - yes they are identical to the parent cell

12. Define crossing over

- when non-sister chromatids of homologous pairs exchange segments of DNA

4. Is a sperm diploid or haploid? How about an egg? How about a skin cell?

Sperm- haploid Egg- haploid Skin Cell- diploid

11. Understand how to read pedigrees (squares vs circles; different shading denotes phenotype or genotype). See video for assistance

Squares- males Circles- females Completely filled in circle or square- that person expresses the gene Half filled in circle or square or a circle or square with lines going through it- person is a carrier for the gene

13. Explain how genes are cloned. Use the terms restriction enzyme, plasmid, and recombinant plasmid in your description

Step 1: Restriction enzymes are used to cut desired gene from chromosome Step 2: Bacterial plasmids are cut using same restriction enzyme and combined with cut gene in a test tube. They combine to form recombinant DNA Step 3: Recombinant plasmid inserted into bacterial cells Step 4: Recombinant cells reproduce, making many copies of the gene (or synthesizing a lot of the protein)

8. Can mutations result in microevolution?

Yes, mutations are the driving force behind all evolution

12. Define the following: a. Gene b. Restriction Enzyme c. Plasmid d. Recombinant DNA e. Transgenic or Genetically Modified Organism

a. *Gene*: a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product b. *Restriction Enzyme*: a bacterial enzyme that cuts DNA at specific locations (nucleotide sequences) c. *Plasmid*: non-essential DNA, in circular form, found in bacteria and plants d. *Recombinant DNA*: a plasmid with foreign DNA inserted into it e. *Transgenic or Genetically Modified Organism*: organisms that has one or more foreign genes from different species inserted into their genome

3. Be able to apply the difference between haploid and diploid a. For example: a rabbit has 40 chromosomes in its body cells, which are diploid. How many different types of chromosomes does a rabbit have? How many chromosomes would there be in the sperm of a rabbit, which is haploid? b. How many different types of chromosomes do humans have? How many chromosomes do humans have in total? Explain why the total number is double the number of different types of chromosomes

a. 20 types of chromosomes and 20 chromosomes in the sperm b. humans have 23 different types; 43 chromosomes in total; the total number is doubled because we get 23 from mom and 23 from dad

8. Be sure you know how to correctly write genotypes for males and females with x-linked traits

a. Below are examples of genotypes using the *only* acceptable technique for writing X-linked traits on the exam. I realize the book uses a different format, however my videos and the homework use the one below: i. Female homozygous for red-green color blindness: XbXb (the X's need to have subscripts at the top right hand side of the X but I cannot do that on here) ii. Female carrier for red-green color blindness: XB Xb (make sure females have alleles for BOTH their X-chromosome) iii. Red-green colorblind male: XbY

11. Be able to use the Genetic Code table to translate an mRNA transcript into a sequence of amino acids a. For example, can you determine the amino acid sequence that would be produced from this sequence of DNA? TACCCGCAGATT b. Hint: you have to transcribe it first

a. Given: TACCCGCAGATT Transcribe it: UACCCGCAGAUU UAC- Tyr CCG- Pro CAG-Gin AUU- Ile

4. Define the following and assign genotypes using the letters "D" and "d" a. Homozygous dominant b. Homozygous recessive c. Heterozygous

a. Homozygous dominant: two copies of the dominant allele ex: DD b. Homozygous recessive: two copies of the recessive allele ex: dd c. Heterozygous: has one dominant and one recessive ex: Dd

10. If a genetic disorder is X-linked recessive: a. How many recessive alleles must a male inherit in order to express the disorder? b. How many recessive alleles must a female inherit in order to express the disorder?

a. Male: one recessive allele ex: XbY b. Female: two recessive alleles ex: XbXb

1. Define the following a. Genetics b. Gene c. Allele d. Homologous Chromosomes

a. The study of the transmission of traits (alleles) from one generation to the next (i.e. from parents to offspring)/ essentially, it is the study of inheritance b. a sequence of DNA that codes for a feature of an organism - there is at least one gene for every feature (characteristic) c. alternative versions of the same gene - there are usually at least 2 alleles for every gene d. chromosomes of the same morphology with genes in the same location; diploid organisms have pairs of homologous chromosomes (homologs), with each homolog derived from a different parent