Semester 2 Exam Review Questions

Summarize the events of interphase.

1st step in cell cycle. The cell spends the most time in this stage. There are 31/2 parts: ~G1 phase- grow rapidly. ~G0 phase- some cells leave cell cycle and won't copy DNA/replicate. ~S phase- DNA replicates and becomes chromatin (DNA all tangled up). ~G2 phase- organelles replicate and cell grows a little more.

Describe the stages of mitosis.

2nd part of cell cycle. There are 4 parts: ~Prophase- the chromosomes condense and become visible. the nuclear membrane breaks down and centrioles move apart to poles. ~Metaphase- the chromosomes move to the center of the cell and line up at the equator. spindle fibers then attach to each centromere (connects the two chromatids together). ~Anaphase- the chromatids are pulled apart to the poles. ~Telophase- the chromosomes uncoil and a nuclear membrane reforms around each set of chormosomes.

Compare cytokinesis between an animal and plant cell.

3rd part of cell cycle. ~Animals-cleave or pinch off. ~Plant- build new cell wall to divide cell in two.

Explain how probability is used to predict the results of genetic crosses.

Prediction of genetic crosses can be with a punnentt square. Depending on the allele pairing, you can either get a homozygous dominant (AA), heterozygous (Aa), or homozygous recessive (aa). The square will help predict the chances of each genotype and phenotype.

Summarize the process of DNA replication.

The process is semi conservative, uses half of the original DNA. First an enzyme, helicase, separates 2 strands of DNA by breaking the H bonds between nitrogen bases. Then another enzyme, DNA polymerase, lays down new nucleotides at the exposed sections on both sides. After, covalent bonds connect the new nucleotides and nitrogen bases with a hydrogen bond. You end with 2 identical DNA moleculs.

Explain the importance of nitrogen-fixing bacteria for many of Earth's ecosystems.

They allow the nitrogen cycle to work by putting nitrogen back into the atmosphere.

Identify the importance of models to ecology.

They represent/describe the components of an ecological system. It helps ecologists understand the environmental interactions and make predictions about possible changes.

What are 3 characteristics that bacterial and viruses have in common? What are the 3 ways they differ?

Viruses vs. Bacteria: ~Not made of cells vs. unicellular. ~Need host cell to reproduce vs. reproduce asexually, binary fission. ~Not living vs. living. Both: ~Made up of DNA/RNA and proteins. ~Contains no nucleus (prokaryotic) ~Vaccines are used to prevent infections. ~Can be harmful and helpful to other organisms.

Describe Charles Darwin's contributions to scientific thinking about evolution.

Went to the Galapagos Islands and realized that the finches and tortoises on each island were different. He came up with his theories of evolution (change in a population over time) and natural selection (unequal reproductive success). He concluded that individuals with the best traits survive and pass traits to offspring that is desirable.

Distinguish between dominant and recessive traits.

~Dominant- represented by an uppercase letter in punnett squares. the trait observed when at least one dominant allele for a characteristic is inherited. ~Recessive- represented by a lowercase letter in punnett squares. a trait that is apparent only when two recessive alleles for the same characteristic are inherited.

Summarize three important processes in the water cycle.

~Evaporation- when water gets hot and turns into water vapor. ~Condensation- when the water vapor cools and forms clouds. ~Precipitation- basically, rain.

Differentiate between the genotype and phenotype of an organism.

~Genotype is the entire genetic makeup of an organism; also the combination of genes for one or more specific traits. ~Phenotype is an organism's appearance or other detectable characteristic that results form the organism's genotype and environment.

Describe how Mendel was able to control how his pea plants were pollinated.

(1)Allowed self-pollination, which a plant can do on its own. (2)To prevent self-pollination he removed all of the anthers from the flowers of the plant. (3)To cross-pollinate the plant, he manually transferred pollen from the flower of another plant to the stigma of the antherless plant.

Explain the concept of a niche.

A niche is the unique position occupied by a species, both in terms of its physical use of its habitat and its function within an ecological community.

Describe the structure of a chromosome.

A rod-like structures made of DNA and proteins. (ps-ignore words in picture. just look at shape of both types)

Explain how anatomy and development of organisms provide evidence of shared ancestry.

Anatomy and Embryology has many parts that all show common ancestry. Parts: ~Homologous Structures (anatomical structures that share a common ancestry) (ex-forelimbs of vertebrates) ~Analogous Structures (structures that are similar in function and appearance but not in structure or origin) (ex-wings from bats, birds, moths) ~Vestigial Structures (structures that serve no function) (ex- pelvic bones in whales) ~Embryology

Name and explain the process of bacterium reproduction.

Binary Fission- a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size.

Explain how biogeography provides evidence that species evolve adaptation to their environment.

Biogeography is the study of organisms in a specific location around the world. Shows evidence in distribution. Example- native australian animals resemble mammals on other continents, but are all marsupials.

Compare the use of biological molecules with other types of analysis of evolutionary relationships.

Biological Molecules compares DNA, RNA, and amino acids. compared to the other evolutionary relationships, it is the most accurate in the fact that closely related species have similar DNA, RNA, and amino acids.

Explain how organisms can undergo coevolution.

Coevolution is when species that interact closely adapt to one another. This usually happen if the organisms have a mutualistic, parasitic, or commensalistic (one benifits, one is neutral) relationship.

Describe how convergent evolution can result among different species.

Convergent evolution is the process by which different species evolve similar traits. It can happen because organisms in different ecosystems/habitats have a similar niche and need the similar trait.

Compare the structure of DNA & RNA.

DNA vs RNA: ~Has thymine(T) vs. has uracil(U). ~Two strands vs. one strand. ~Deoxyribose sugar vs. ribose sugar.

Describe the role of decomposers in the nitrogen cycle.

Decomposers break down the bodies of dead organisms, resulting in nitrogen being returned to the soil as ammonia. In some conditions denitrifying bacteria in the soil break down nitrates and return nitrogen to the air.

Explain how divergent evolution can lead to species diversity.

Divergent Evolution happens when an isolated population of species evolve independently. It can lead to diversity in species because the organism has to adapt/evolve to its new surroundings while the other organism (same species) is adapting/evolving to a different environment. Thus, creating different types of the species.

Use a Punnett square to predict the results of monohybrid and dihybrid crosses.

Example question (dihybrid): ~In guinea pigs Long Hair (H) is dominant to Short Hair (h), and Black (B) is dominant to Brown (b). *Be sure to show both F1 and F2 as well as phenotype, genotype, phenotypic ratio, and genotypic ratio.

Summarize the history of scientific ideas about evolution.

First, Jean Baptiste Lamarck (1744-1829) had the idea of acquired characteristics, but thought they were passed to offspring (wrong). Then Charles Darwin (1809-1882) came up with the idea of natural selection and evolution. He when the the Galapagos Islands and the finches where different on each island.

Relate several inferences about the history of life that are supported by evidence form fossils and rocks.

Fossils are the remains or traces of organisms that died (usually extinct). The fossils show: ~Transitional species- the intermediate states between an ancestral form and that of its descendants. ~Absolute age- radiometric age. ~Relative age- compare to geologic time and know fossils.

Evaluate the contributions of Franklin & Wilkins in helping Watson & Crick discover DNA's double helix structure.

Franklin and Wilkins invented x-ray photos of "the factor" (which we now know is DNA). Watson and Crick described the DNA molecule form the x-ray and came up with their theory.

Explain the role of sex chromosomes in sex determination.

If an organism has two X chromosomes for the 23rd chromosome pair, than it becomes a female. If the organism has one X and one Y chromosome, it becomes a male.

Explain how geneticist can detect and treat genetic disorders.

Geneticist can create a karyotype of your chromosomes. They can also look at portions of suspected DNA to see if any mutations occurred.

Describe the steps in Mendel's experiments on true-breeding garden peas.

He started with white and violet true/pure breeds (P generation). Then cross-pollinated the P generation to get the F1 generation. They were all violet. Then self pollinated the F1 generation to get the F2 generation, which was both white and violet.

Describe an example showing the effects of interdependence upon organisms in their environment.

Interdependence is how an organism's survival depends on the living and nonliving parts of their environment. An example is that a human could not survive without the plants that produce oxygen. Conversely, plants depend on the release of CO2 from human's respiration to go through photosynthesis.

Identify the importance of learning about the human genome.

It is important because it uses information from DNA to develop new ways to treat, cure, or even prevent the thousands of diseases that afflict humankind. As well as help us better understand ourselves and the way we work.

Summarize the events of Meiosis 1 & Meiosis 2.

Meiosis 1 has 4 stages: ~Prophase 1- the chromosomes condense and become visible. the nuclear membrane breaks down and centrioles move apart to poles. The homologous chromosomes pair up. ~Metaphase 1- homologous chromosomes line up at the equator, but across form each partner. spindle fibers attach to each centromere. ~Anaphase 1- homologous chromosomes seperate and move to the poles. ~Telophase 1- the nuclear membrane reforms and the chromosomes uncoil. (cytokinesis) Meiosis 2 has 4 stages: ~Prophase- the chromosomes condense and become visible. the nuclear membrane breaks down and centrioles move apart to poles. ~Metaphase- the chromosomes move to the center of the cell and line up at the equator. spindle fibers then attach to each centromere (connects the two chromatids together). ~Anaphase- the chromatids are pulled apart to the poles. ~Telophase- the chromosomes uncoil and a nuclear membrane reforms around each set of chormosomes.

What are 3 difference between mitosis and meiosis?

Mitosis vs Meiosis: ~Makes body cells (somatic) vs makes sex cells (gametes). ~Makes 2 cells vs makes 4 cells. ~Makes diploid cells vs makes haploid cells. ~Makes clones vs makes genetically different cells. ~One process vs 2 processes.

Explain how a testcross (punnentt square) is used to show the genotype of an individual whose phenotype expresses the dominant trait.

Punnent squares show the probability of a given genotype. If the gene has at least one dominant allele then the phenotype will be what the dominant allele expresses. If there are no dominant alleles, then the recessive allele will be expressed.

Describe the common methods used to identify bacteria.

Structure: ~Shape: bacillus (rod), coccus (sphere), or spirillum (spiral). ~Arrangement: diploid (paired), staphylo (grape-like clusters), or strepto (chains). Or, Gram-/+ ~Gram +: lots of carbs and proteins in cell wall= retains purple dye. ~Gram -: little carbs and proteins in cell wall= doesn't retain purple dye, dyes a pinkish color instead.

Describe how errors are corrected during DNA replication.

The DNA polymerase is a "proof reader", if it finds a mistake, it fixes it.

Describe how complementary base pairing guides DNA replication.

The DNA polymerase knows what other nitrogen base pairs with the nitrogen base; therefore, replacing the nitrogen base the same type that was previously there, so it can replicate the strand.

Define the biological process of evolution.

The fact that all organisms descend from a common ancestor and through that descend, the process of organism's characteristics change or adapt over time to between suit their environment.

Describe the importance of the genetic code.

The genetic code codes for every part/function in your body. The genetic code make the proteins that make up your phenotype and preforms the function of your body, needed to live, as well as reproduce.

Relate the role of the base-paring rules to the structure of DNA.

The nitrogen bases adenine (A) and thymine (T) pair with eachother. The nitrogen bases cytosine (C) and guanine (G). These bonds (hydrogen) hold the two "legs" together.

Identify a key theme in ecology.

The study of the interactions of living organisms with one another and with their environment.

Outline the flow of genetic information in cells from DNA to protein.

There are 2 parts of Protein Synthesis (transfer of genetic info to cells to make proteins), transcription and translation. ~Transcription- the RNA Polymerase attaches to the DNA to open it up. RNA nucleotides match up to DNA and form covalent bonds. then the RNA polymerase reaches terminator site on DNA and stops. now it has a mRNA molecule with info to build the protien. ~Translation- mRNA comes to the ribosome. process starts with AUG, and the tRNA attaches to the P site and the tRNA's anticodon matches up with the mRNA's codon. the message from the mRNA codon is translated to the amino acid. the A site is filled with new tRNA, the amino acid is named. a peptide bond connects the 2 amino acids and the tRNA leaves the P site and everything shifts over. new tRNA enters the A site and the process continues until it reaches a stop codon (UAG, UGA, UAA). all the molecules leave the ribosome and the protien/polypeptide is made.

Describe how Mendel's results can be explained by scientific knowledge of genes and chromosomes.

There are dominant and recessive genes. He started with the P generation, violet (AA) and white (aa). Then the F1 generation was cross-pollinated, so each flower got Aa, since violet is dominant, they all turned out violet. Then the F2 gerneration was a mix of 1/4 AA, 1/2 Aa, and 1/4 aa. That means that 3/4 flowers will be violet because they have a dominant, while 1/4 will be white because they have two recessive.

Identify the role of enzymes in the replication of DNA.

There are two important enzymes in replicating DNA. ~Helicase- separates 2 strands of DNA by breaking the hydrogen bonds between the nitrogen bases. ~DNA Polymerase- lays down new nucleotides at the exposed sections on both sides. also is a proof reader.

Summarize the different patterns of inheritance seen in genetic traits & disorders.

There can be changes in number or structure of chromosomes. Such as: (the original chromosome is ABC*DEF) ~Deletion (AC*DEF) ~Duplication (ABBC*DEF) ~Inversion (AED*CBF) ~Translocation (chrome 1- ABC*JKL, chrome 2- GHI*DEF)

Differentiate a monohybrid cross from a dihybrid cross.

~A monohybrid cross is a cross between individuals that involves on pair of contrasting traits. (4 boxes) ~A dihybrid cross is a cross between individuals that have different alleles for the same gene. (16 boxes) (picture is a dihybrid)

Compare abiotic factors with biotic factors and give two examples of each.

~Abiotic Factors- an environmental factor that is not living. examples- temperature, sunlight, weather ~Biotic Factors- an environmental factor that is living. examples- food, availability of a mate, predators, disease.

Describe 2 mechanisms that allow organisms to survive in a changing environment.

~Acclimation- an organism's change in response to a change in the organism's environment. ~Regulator gene- a genetic unit that regulates or suppresses the activity of one or more structural genes.

Identify three habitats of archaea.

~Animal intestines ~Sulfur vents ~Very salty water ~Oxygen free environments

State the five different levels of organization at which ecology can be studied.

~Biosphere- the thin volume of Earth and its atmosphere that supports life. all organisms are found. ~Ecosystem- includes all of the LIVING organisms and NONLIVING environment found in a particular place. Ex- pond. ~Community- all the interacting organisms LIVING in an area. Ex- fish, turtles, plants, algae, and bacteria. ~Population- includes all the members of a species that live in one place at one time. Ex- turtles. ~Organism- a single organism.

Outline the major steps in the carbon cycle.

~Carbon enters the atmosphere as carbon dioxide from respiration and combustion. ~Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis. ~Animals feed on the plant passing the carbon compounds along the food chain. Most of the carbon they consume is exhaled as carbon dioxide formed during respiration. The animals and plants eventually die. ~The dead organisms are eaten by decomposers and the carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion.

Summarize the role of covalent and hydrogen bonds in the structure of DNA.

~Covalent Bond- holds the phosphate and deoxyribose together. (phosphodiester bonds in picture) ~Hydrogen Bond- holds the nitrogen bases together.

Distinguish between diploid and haploid cells.

~Diploid- all somatic (body) cells. have two autosomes for each homologous pair (46 chromosomes total). (get one from mom, one from dad) ~Haploid- all gamete (sex) cells. contain only one set of chromosomes. have half the number of chromosomes that are present in diploid cells, thus only one autosome of each homologous pair and only one sex chromosome (23 total).

Know the differences between the 3 Homo species.

~Homo habilis- 2 mya. "handy man", 1st tool maker. found in Africa. smallest brain and possibly capable of some speech. ~Homo erectus- 1.5 mya. had more sophisticated tools and fire. found in Africa, Asia, and Europe. 1st to stand upright, capable of speech, and social (in groups). ~Homo sapiens- 300,000 ya. "wise man". 1st known painters. buried the dead with ceremonies and took care of sick/injured. (humans)

State two laws of heredity that were developed from Mendel's work.

~Law of Segregation- each allele separates from the other when gametes form. ~Law of Independent Assortment- pairs of alleles of different genes separate independently when gametes form.

Relate the concepts of adaptation and fitness to the theory of natural selection.

~Natural Selection- the process of individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do; a theory to explain the mechanism of evolution. ~Fitness- a measure of an individual's hereditary contribution to the next generation. ~Adaption- an anatomical, physiological, or behavioral change that improves a population's ability to survive in their given environment.

Compare artificial selection and natural selection.

~Natural Selection- when individuals with the best traits to survive and pass their traits to their offspring. ~Artificial Selection- when humans chose parents for the next generation.

List the four major biogeochemical cycles.

~Nitrogen Cycle ~Phosphorus Cycle ~Water Cycle ~Carbon Cycle

Summarize the major steps of the phosphorus cycle.

~Over time, rain and weathering cause rocks to release phosphate ions and other minerals. This inorganic phosphate is then distributed in soils and water. ~Plants take up inorganic phosphate from the soil. The plants may then be consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decays, and the organic phosphate is returned to the soil. ~Within the soil, organic forms of phosphate can be made available to plants by bacteria that break down organic matter to inorganic forms of phosphorus. This process is known as mineralisation. ~Phosphorus in soil can end up in waterways and eventually oceans. Once there, it can be incorporated into sediments over time.

Describe the 3 parts of a nucleotide.

~Phosphate Group ~Sugar (Deoxyribose) ~Nitrogenous base (A,T,C, or G)

Identify the differences in structure between prokaryotic chromosomes and eukaryotic chromosomes.

~Prokaryotic- The DNA strands are in a ring shape and not tightly compacted by a histone. ~Eukaryotic- The DNA wraps tightly around proteins (histones). In rod-shaped chromosomes.

Explain the differences between a sex chromosome and autosome.

~Sex Chromosomes- determine the sex of an organism and may also carry genes for other characteristics. In humans they are X or Y. XX = female, XY = male. ~Autosome- all the other chromosomes in an organism (44). all "X" shaped pairs.

Distinguish between sex chromosomes and autosomes.

~Sex chromosomes- either X or Y. You get one from each parent and it determines what gender you are. (XX in females and XY in males). There are also many sex-linked traits/diseases. each somatic cell has 2 sex chromosomes. ~Autosomes- all other chromosomes that aren't sex chromosomes. "X" shaped. each somatic cell has 44 autosomes.

Compare spermatogenesis and oogenesis.

~Spermatogenesis- the use of meiosis to produce sperm cells. produces 4 usable sperm cells. ~Oogenesis- the use of meiosis to produce mature egg cells/ova. produces 1 usable ovum (mature egg cell) and 3 polar bodies, which will eventually degenerate.

What are 3 characteristics that most primates have in common~

~Strong three-dimensional and color vision ~prehensile appendages (can grasp) ~large brain pars relative to size ~omnivorous teeth ~communication ~infant care ~opposable thumbs ~social organization

Compare the role of mRNA & tRNA in translation.

~mRNA- are RNA nucleotides matched up to DNA and form covalent bonds. it contains the info to make a protein and names the protein in the ribosome. ~tRNA- has the anticodon to pair with the mRNA's codon in order to form the protein.