Biology 101 Study Guide -Test #3 Chapters 8-9 Dr. Sriyani Rajapakse

Bio 101 Test 3 Study Guide Test 3 will cover Chapters 8 & 9

Test Format: Multiple choice, matching, true/false, label parts of diagrams

For each chapter:

·  Read “Reviewing the concepts”

·  Do “Connecting the concepts”

·  Try to answer as many questions as you can in “Testing your knowledge”

Chapter 8: Cellular basis of reproduction and Inheritance

·  What are the two major types of reproduction and what are the differences between them? Amoeba reproduces by which type? Which one produces offspring with unique combination of traits?

·  How do bacteria (Prokaryotes) reproduce? What is the special term given for this process? Is this an example of asexual or sexual reproduction? Is there a spindle involved in this process?

·  Learn the phases of the cell cycle. In which phase does the sister chromatids form? Cells that do not divide, like nerve cells, are in which phase? What is the genetic material called at this point?

·  Eukaryotic cells divide by mitosis and meiosis. Which cells are formed by mitosis? Which cells are formed by meiosis? Know the difference between these two methods of cell division.

·  What is the role of centriole (located inside centrosome) in cell division? Do plant cells have centrioles? No. What are spindle fibers? What are spindle fibers made out of? How do spindle fibers help in cell division?

·  Know the phases in mitosis (in order) and learn what is happening in each phase.

·  When in mitosis do chromatin fibers condense into visible chromosomes? Draw a chromosome and label centromere and sister chromatids. What are sister chromatids?

·  How many chromosomes are present in a human somatic cell? 46 (Somatic cells are all body cells except gametes)

·  How many sister chromatids are present in a human cell that is in G2? 92 (Each chromosome has been duplicated and consists of a pair of sister chromatids joined at the centromere.)

·  Mitosis: By the end of metaphase, how many chromosomes are present in one human cell? 46. How many chromatids are present in one human cell? 92

·  Mitosis: By the end of anaphase, how many chromosomes are present in one cell? 92
(Once the sister chromatids separate, they are considered to be individual chromosomes.) How many chromatids are present in one cell? 0

·  Mitosis: By the end of telophase, how many chromosomes are present in one nucleus within the human cell? 46. Are the nuclei identical or different? Identical

·  What is cytokinesis? How is this different between plants and animals? What is a cell plate? What is a cleavage furrow?

·  By the end of cytokinesis how many chromosomes are present in one human cell? 46. How many chromatids are present in one human cell? 0 (Chromatids will not be present until after the next S phase.)

·  What are the factors that control cell division? What is meant by density-dependent inhibition? Do cancer cells have by density-dependent inhibition?

·  Campare the cell division of normal cells and that of cancer cells.

·  What is G0 phase and what is its importance? Name a type of cell in your body that is in G0 for most of your adult life.

·  Meiosis: Learn where is meiosis taking place in animals and in plants?

·  What are homologous chromosomes? What is meant by diploid (2n) and haploid (n)? Learn the human life cycle and know when meiosis occurs and gametes are formed? When does mitosis take place? Follow the chromosome sets (2n vs n) in the cycle. From whom did you inherit one set of homologous chromosomes? and the other set from?

·  What are autosomes and sex- chromosomes? What autosomes and sex chromosomes do males have? Females have?

·  How is meiosis different from mitosis? Name three differences. Which one results in gamete (eggs and sperm) formation?

·  How many cell divisions are in meiosis? How many cells result? What are their n numbers? (2n or n)

·  In which phase of mitosis crossing over takes place. What are the X shaped structures formed are called? (Chiasma).

·  What is the result of crossing over in gametes? Produces recombinant gametes which have different allele combinations than parental gametes (study the mouse chromosomes).

·  What is nondisjunction? What is the outcome for gametes?

·  What is a karyotype? Can you ID a female karyotype from a male karyotype? How is a karyotype made?

·  What is Trisomy 21? How can these individuals form? What are their characteristics? Is meiosis in mother or father responsible for this?

·  What are some abnormalities in sex chromosome numbers?

·  What are the four kinds of structural alterations that chromosomes can go through? deletion, duplication, inversion and translocation.

·  Give an example where a translocation between 2 chromosomes can lead to cancer

Chapter 9: Genetics & Inheritance

·  9.2 Why is Mendel called the “Father of genetics”? Which organism did he use? Why is it a good choice?

·  9.2 Know the meaning of terms used in genetics, self-fertilization, cross-fertilization, true-breeding, hybrid, P generation, F1 generation, F2 generation

·  9.3 & 9.4 Know the difference between the similar terms such as homozygous vs. heterozygous, genotype vs. phenotype, allele vs. gene, homologous chromosomes vs. heterologous chromosomes

·  9.3 What is a monohybrid cross? Do a Punnett square for a monohybrid cross. Write in vertical order, genotypes of parents, gametes of parents, F1 genotype and phenotype, F2 genotypes and phenotypes. What is Mendel’s monohybrid ratio?

·  9.5 What is a dihybrid cross? Do a Punnet square for a dihybrid cross. Write in vertical order, genotypes of parents, gametes of parents, F1 genotype and phenotype, F2 genotypes and phenotypes. What is Mendel’s dihybrid ratio?

·  9.3 & 9.5 What are Mendel’s two laws? What do these really mean? Hint: First law applies to alleles of a single gene. The second law applies to alleles of more than one gene. Explain these two in terms of chromosomal behavior during meiosis. (See module 9.16)

·  9.6 What is a test cross? Why do a test cross? How would you do a test cross? What is the test cross ratio for one gene?

·  9.9 What are the two types of inheritance patterns for inherited genetic disorders?

·  9.9 Name two human disorders inherited in autosomal recessive manner, (Table 9.9 lists sickle cell as a recessive disorder, it is not correct. We learned in the lab that it is codominant, which is correct)

·  9.9 Name two human disorders caused by autosomal dominant genes?

·  9.11 What is incomplete dominance? Give an example

·  9.12 What is codominance? Give an example

·  9.12 Know the genetics behind the ABO blood groups in humans. Know the relationship among the alleles (i.e., dominant/recessive/codominant/incomplete dominance etc). A man who has type B blood marries a woman who has type A blood. Could they have children of blood groups A, B , AB or O? Work this out.

·  9.13 What is pleiotropy? Give an example.

·  9.14 What do we call characters that are controlled by many genes: Polygenic traits? Give examples. What shape is the distribution of a polygenic trait?

·  9.15 Does the environment have more of an effect on single gene traits or polygenic traits?

·  9.17 What are linked genes?

·  9.20 Know the X-Y sex determination system in humans. We covered this in detail in the lab.