Natural Science 100 Lecture

Natural Science 100 Lecture

Review for the 5thMidterm

(This document was revised at 10:20 AM on April 8, 2009)

NOTE:

1. Underlined and bolded items within each major (capitalized) section are emphasized on the midterm.

2. Check the website:

or for an updated version of this review so as to have the most accurate version for study purposes.

3. Midterm 5 will have only 35 questions (worth ¾ points each) instead of the usual 40 questions. The 5 missing questions will be given to you on the course final and those 5 questions will cover Ecology (Lecture 17).

4. Bring a Scantron ParSCORE Test Form No. F-20788-PAR (its light blue with 1-50 on side one and 51-100 on side 2 – same as one used by other teachers)

MITOSIS – Lecture 11

1. Know that there are three main reasons for cell division: (1) surface area to volume decreases, (2) genetically programmed, and (3) external stimuli.
2. Know DNA can exist in two forms which are (1) chromatin = uncondensed DNA and (2) chromosomes = highly condensed DNA.
3. Know that a single (one) DNA double helix is also known as a chromatid.
4. Know that cell division in a eukaryotic cell is subdivided into (1) karyokinesis (also called mitosis) = division of the nuclear material or the DNA, and (2) cytokinesis = division of the cytoplasm
5. Know that Interphase is not a phase of mitosis and it precedes mitosis.
6. Know that during interphase (1) the DNA is called chromatin and (2) DNA replication occurs.

1. Know that the following occur during prophase (first phase of mitosis): (1) chromatin becomes condensed into chromosomes, (2) nuclear membrane disappears, (3) nucleolus disappears, and (4) spindle fibers (a type of microtubule) attach to centromeres of the chromosomes.
2. Know that in metaphase that chromosomes line up in a single line in the center of the cell
3. Know that in anaphase that sister chromatids (which are part of the same chromosome) will separate from each other and move to opposite sides of the cell.
4. Know that in telophase that (1) chromosomes de-condense back into chromatin, (2) the nuclear membrane reappears, and (3) the nucleolus reappears.
5. Know that cytokinesis occurs during telophase.
6. Knows that telomeres are extra regions of DNA located on the ends of chromosomes, and that these extra regions break off and are lost during the normal activities of the cell.
7. Know that in older cells all of the telomeres have usually broken off and that normal useful DNA then starts to break off which can result in cell death; this may be responsible for aging.
8. Know that teleomerase is an enzyme that prevents telomeres from breaking off and thus helps to prevent cell death, and that telomerase is found in high concentrations in cancer cells.

MEIOSIS – Lecture 12

1. Know that meiosis is special kind of cell division that reduces the number of chromosomes in half and is therefore known as reduction division.
2. Know that a diploid (2N) cell (or nucleus) contains two sets of chromosomes; one set inherited from the female parent and one set inherited from the male parent.
3. Know that a haploid (1N) cell contains one set of chromosomes.
4. Know that sperm cell is a haploid cell (1N); and that an egg cell is a haploid cell (1N).
5. Know that when a sperm cell (1N) units with an egg cell (1N), that the resulting cell is called a zygote and that the zygote is a diploid (2N = 1N + 1N) cell.
6. Know that a human egg has 23 chromosomes and that a human sperm has 23 chromosomes, and that each of the 23 chromosomes in the egg is homologous to a specific chromosome in the sperm.
7. Know that in humans, when the sperm and egg unit to form a zygote, that the zygote now has 23 pairs of homologous chromosomes or a total of 46 chromosomes (23 x 2 = 46)
8. Know that the main difference between mitosis and meiosis is as follows: in mitosis homologous chromosomes line up in a single line in the center of the cell, whereas, in meiosis, homologous chromosomes line up adjacent to (next to) each other.
9. Know that in mitosis, 1, 2N cell will produce a total of 2, 2N cells which are genetically identical to each other or clones of each other.
10. Know that in meiosis, 1, 2N cell will produce a total of 4, 1N cells which are not genetically identical to each other and are therefore not clones of each other.
11. Know that crossing over can only occur in meiosis because homologous chromosomes line up next to each other, whereas in mitosis homologous chromosomes do not line up next to each other.

GAMETOGENESIS – Lecture 13

1. Know that in spermatogenesis, (1) the primary spermatocyte is 2N, (2) the secondary spermatocytes are 1N, (3) the spermatids are 1N, and (4) the sperm (or spermatozoa) are 1N.
2. Know that each spermatid undergoes a change of shape (morphogenesis) and turns into a swimming sperm cell with the following structure: (1) head (contains nucleus and acrosome), (2) a middle piece (contains mitochondria), and (3) the tail (flagellum).
3. Know that in oogenesis, (1) the primary oocyte is 1N, (2) secondary oocyte is 1N, (3) the ootid is 1N, and (4) all polar bodies are 1N.
4. Know that polar bodies will die, even if they combine with a sperm, because neither the sperm nor the polar bodies have enough cytoplasm to survive.

FERTILIZATION – Lecture 13

1. Know that fertilization consists of two independent acts, (1) egg activation and (2) amphimixis.
2. Know that egg activation occurs when the sperm makes contact with the egg cell membrane.
3. Know that amphimixis is the process by which the sperm nucleus combines with the egg cell nucleus.
4. Know that parthenogenesis is egg activation in the absence of amphimixis.
5. Know that a sperm cell is 1N and an egg (ovum) is 1N and that when they combine to form a zygote, that the zygote is 2N (1N + 1N = 2N).

GENETICS – MENDEL AND MORGAN – Lecture 14

1. Know that Mendel is considered to be the founder of modern genetics.
2. Know through his work in genetics that Mendel established the relationship between meiosis and genetics.

3. Know that Mendel’s work was mainly ignored during his lifetime, but, that it was resurrected and validated by Morgan in the early 1900s.

GENETICS – BASIC TERMS – Lecture 14

1.Know that a gene is defined as that section of DNA that is responsible for a particular protein (or trait), such as eye color, leaf shape, and certain diseases (genetic diseases).

2.Know that genotype refers to the actual genes present in an organism for a particular trait; for example the gene for normal hemoglobin is H, whereas, the gene for sickle cell anemia is h – on the test you would be given the letters representing a gene.

3.Know that because most living things are 2N or diploid that living things will have two genes for every trait; one gene inherited from the male parent and one gene inherited from its female parent.

4.Know that (1) if an organism inherits two identical genes for a particular trait that the genotype is said to be homozygous (such as HH or hh) and (2) if an organism inherits two genes with are not identical to each other, then the genotype is said to be heterozygous (such as Hh).

5.Know that an organism’s phenotype is the appearance of the organisms, and that appearance can include physical, chemical, or behavior characteristics. For example, sickle cell anemia is a phenotype.

6.Know that an allele is the term used to describe alternate forms of genes for the same trait; for example the gene H is the allele (alternate form of the gene) to h.

7.Know that the physical location on a chromosome in which a gene (or allele) is located is known as the locus (loci is more than one locus).

8.Know that the allele T for Tall plant will produce a tall phenotype in either the TT (homozygous) or Tt (homozygous) genotype, whereas, t for short plant will only produce a short plant in the tt genotype, therefore, T is dominant to t because when T is with t, T dominates the expression and the plant expresses only the T trait for tall plant. Also, t is recessive because it will only produce short phenotype it is the tt genotype.

9.Know that in incomplete dominance that one allele is NOT dominant over another allele, but instead when two alleles interact there is a blending effect. For example R is for red flower color and W is for white flower color; and the genotype RR is phenotypically red, WW is white, and RW is not red or white, but it is pink, which is intermediate between red and white.

10.Know that in codominance that one allele is NOT dominant over the other allele, but instead when two alleles interact together, that there is an equal expression of each allele. For example if allele IA is for blood type A and allele IB is for blood type B, that the IAIA genotype produces type A phenotype (blood type A), that IBIB produces blood type B and that IAIB produces blood type AB or phenotype AB. AB expresses equally type A and type B proteins which equals AB blood. It is not blending as in incomplete dominance, but instead it is equal expression of each allele.

11.Know that in pleiotropy that one allele can effect one phenotype #1, and that phenotype #1 can effect phenotype #2 and that phenotype #2 can effect phenotype #3 and so on. For example the H is the dominant allele for normal hemoglobin and h the recessive allele for sickle cell hemoglobin, then the genotype hh results in a phenotype that results in a misshapen hemoglobin (protein) molecule……this results in sickled red blood cell which another phenotypic change………this results in organ damage which is yet another phenotypic change………and so on.

12.Know atavism is a term that describes phenotypes that appear as “throw backs” to more primitive evolutionary characteristics, such as gill slits in humans. There is disagreement as to the origin of these phenotypes; are they from genes that are part of our genetic evolutionary past or are they due to more recent mutations that simply look like characteristics from our evolutionary past?

13.Know that in multiple alleles at the same loci that a population can have three or more alleles for a particular trait but that any individual member of that population can only have one or two of these alleles. For example, black and white coat color in dogs is due to four alleles. S is the allele for black, Si = black with some white fur, Sp is white with some black fur, and Sw is all white fur. An animal can be SS or SSw or SpSw for example but not SSSw or SiSpSw.

EVOLUTION – Lecture 15

1.Know that Lamarck proposed the theory of the inheritance of acquired characteristics.

2.Know that the inheritance of acquired characteristics means that if an organism acquires a characteristic during their life time that this characteristic will be passed on to the next generation of offspring produced by that organisms.

3.Know that Darwin published his theory on evolution in a book called “The Origin of Species (by natural selection)” in the mid 1800 and that he based his book on the observations that he made while cruising the world.

4.Know that Darwinbased some of his evolutionary theory on observations that he made when he visited the GalapagosIsland off of the coast of South America.

5.Know that Darwin’s Finches were thought by Darwin to evolve into separate species by adapting (evolving) into various habitats by natural selection.

6.Know that in natural selection the members of a population with the best adapted characteristics will reproduce more often that less well adapted members of a population and therefore it is those best adapted members that pass on their characteristics to the next generation.

7.Know that microevolution is the change in the gene frequency within a population over time.

8.Know that the following five factors are known to influence microevolution:

(1) mutation, (2) non random mating, (3) genetic drift, (4) gene flow, and (5) natural selection.

9.Know that mutation can be either a change in DNA nucleotides or a change in chromosome structure.

12.Know that in non random mating that certain members within a reproducing population select other member with which to mate rather than mating randomly with in the population; and that this results in the accumulation of genetic factor in isolated groups within the population.

13.Know that in gene flow, members of a population will alter the genes in that population if the individuals migrate to another region.

14.Know that in genetic drift that if certain members of small populations are killed or in some other way leave the population that the gene frequency is altered much more dramatically that if the population was larger.

15.Know that in natural selection that there is a higher reproductive rate for those better adapted members of a population than for those less well adapted members of the same population – earlier known as survival of the fittest.

16.Know that a species is a group of naturally or potentially interbreeding populations that are reproductively isolated from other such populations.

17.Know that geographic isolation results in a reproducing population being separated by some sort of physical or ecological barrier that in turn results the build up of mutations not shared by the now isolated populations; and that once isolated, these new mutations could result in the inability of those newly isolatedpopulations to reproduce with each other, thus forming separate species.

ORIGIN OF LIFE – Lecture 16

1.Know that some scientist think that in the history of the earth the following small molecules were formed first: (1) methane or CH4), (2) carbon dioxide or CO2, (3) water or H2O, (4) ammonia or NH3, (5) hydrogen sulfide or H2S, (6) phosphate or PO43-

2.Know that some scientist feel that from the small molecules in #1 above that the following larger molecules were formed: (1) amino acids, (2) sugars, (3) phospholipids, and (4) RNA nucleotides.

3.Know that the Murchison Meteorite (from our solar system) which crashed to earth in 1969 had 90 amino acids of which only 19 were similar to those found on earth – evidence of life

4.Know the following details of the RNA World Hypothesis:

Ribozyme (RNA) self replicates more RNA

RNA forms ribosomes (organelle made of RNA and protein)

Ribosomes form proteins

Proteins (enzymes) out compete RNA catalytically

Protein becomes dominant form

5.Know that cells probably appeared in the following order:

(1) Anaerobic cells

(2) Photosynthetic cells

(3) Aerobic cells

(4) Eukaryotic cells (formed by endosymbiosis)

6.Know that multicellularity had the advantage of cell specialization over single celled organisms.

ORIGIN OF MULTICELLULARITY – Lecture 16

1.Know that the volvocine series demonstrates the theory of the origin of multicellularity in a succession of more complex organisms which include (1) Chlamydomonas (1 cell), Gonium (4-16 cells), Eudorina (16-32 cells), Pleodorina (32-128 cells) and Volvox (thousands of cells).

2.Know that Gonium appears to be a collection of 4-16 Chlamydomonas cells held together in a gel-like material, representing a very primitive multicellular organisms whereby all cells function in photosynthesis and motility.

3.Know that Eudorina appears to be a collection of 16-32 cells that all behave the same when there are only 16 cells, but, when there are 32 cells 4 of them specialize for motility only and the rest of the cells specialize for reproduction only. The is the simplest example of division of labor among cells.

KINGDOMS OF LIFE – Eubacteria (bacteria) – Lecture 16

1.Know that the Kingdom Bacteria includes the following (1) only prokaryotic cells, (3) cells that are either classified as coccus (spherical), bacillus (rod shaped), or spiral shaped, and (4) ecological roles of decomposers, disease producers, or symbiotic with other species.

KINGDOMS OF LIFE – Protista – Lecture 16

1.Know that Protista consists of (1) mostly unicellular organisms, (2) eukaryotic cells, (3) ecological roles include the first steps in the food chain such as phytoplankton (plant like Protista) or zooplankton (animal like Protista called protozoa).

2.Know that phytoplankton (single celled, plant like algae) are photosynthetic and that while they make up less than 1% of the earth’s biomass (mass of all living material on earth), they are responsible for more than 50% of the earth’s photosynthesis and thus 50% of the world production of food and oxygen gas.

KINGDOMS OF LIFE – Fungi – Lecture 16

1.Know that Fungi are (1) unicellular or multicellular, (2) function as decomposers in nature, used in industry , used in medicine, and some produce disease, (3) no photosynthesis, and (4) common examples included mushrooms, yeast, and mold.

KINGDOMS OF LIFE – Plant subgroups (Bryophytes, Fern, Gymnosperms, Angiosperms) are below:

BRYOPHYTES – Lecture 16

1.Know that the Bryophytes have the following characteristics (2) no vascular system (2) relatively small size, (3) acquire nutrients by diffusion (4) live in moist habitats.

2.Know that the most familiar form of a Bryophyte is called a moss.

FERNS – Lecture 16

1. Know that the Ferns (1) have a vascular system present (internal vessels for delivering water and nutrients from soil to all cells) (2) can live in dryer habitats than can bryophytes because of the vascular system.

GYMNOSPERMS – Lecture 16

1.Know that Gymnosperms (conifers, pines) have the following characteristics (1) vascular system well developed(2) can live in dry habitats because of a well developed vascular system, and (3) produce seeds.

ANGIOSPERMS – Lecture 16

1.Know that (1) angiosperms can adapt to driest of habitats, (2) angiosperms have a well well development vascular system and, (3) produce flowers, seeds and fruits.

2.Know that flowers attract insect and bird pollinators by (1) odor, (2) nectar guides, (3) flower shape and (4) flower color and that the flowers provide food (pollen and nectar) to the insects and birds.

3.Know that many flowers and insects (such as bees) have coevolved their structures and functions for flower pollination and for providing food for the insect.

KINGOMS OF LIFE – Animals – Lecture 16

Porifera

1.Know that the phylum Porifera has the following characteristics: (1) multicellular, but no true tissues,(2) sessile (do not move), and sponges are example.

Cnidaria

1.Know that members of the Phylum Cnidaria have the following characteristics: (1) True tissues (2) a gastro vascular cavity, (3) Nerve cells which form a nerve net, no brain, (4) they are basically just a stomach with arms, and (5) jellyfish and sea anemone are examples.