Consider the diagram below and answer the following questions: • The image shows [Select] chromosome(s). • How many chromosomes are shown in the image? [Select] Which term best describes what is shown by the bracket labeled "a"? [Select] ●

• Illustrate the chromosome changes in interphase and mitosis using a diploid cell that is 2n=4 (two large and two small chromosomes). • Label the circles as G1 and G2 stages of interphase and each phase of mitosis (in order). Draw the chromosome in each circle using the following guidelines. 1) For unreplicated chromosome draw a line (/) and for replicated chromosome draw an X. 2) For simplicity, do not indicate that the chromosomes are decondensed chromatin during interphase. ● 3) Skip drawing the nuclear membrane or spindle fibers, since we are focusing on the chromosomes. • Label genes in the resulting daughter cells as A/a and B/b. (These letters represent genes which are at icular places along the DNA molecule. Each chromosomes can have a thousand genes but we are focusing on these two.

1. In the simple picture below we are focusing on the chromosomes. Notice that the chromosomes are condensed and the nuclear membrane and spindles are not shown. a. Please label the following and indicate with arrow(s): sister chromatids, a pair of homologous chromosomes, a centromere. b. Label the part of diagram that indicates a double helical molecule of DNA and highlight it with a thick line. c. How many molecules of DNA are shown in this picture? d. Is this cell haploid or diploid (circle one). How do you know? e. Below the diagram, indicate the ploidy (number of sets of information) and the number of chromosomes X n= ploidy (# of sets of information) X X M # of 2. The circle below represents the cell cycle. chromosomes a. Write the phases (G1, G2, M and S) in the appropriate sections. b. Which phase results in identical sister chromatids? c. In which phase do sister chromatids separate?

In the lab we use beaded plastic models to represent an unduplicated chromosome: (first picture)   Imagine that you put together 8 chromosomes as shown below: (2nd picture)   and then you join the sister chromatids together at their (magnetic) centromeres. How many chromosomes are represented by four sister chromatids joined together at their (magnetic) centromeres ?         2     4

a. What is the diploid number of chromosomes for a human? b. What is the haploid number of chromosomes for a human? Which cells are considered diploid, gametes or somatic cells? C. d. Which cells are considered haploid, gametes or somatic cells?

18. This question refers to the following schematic diagram of two normal chromosomes and five aberrant forms (A through E) of those chromosomes. (Circles represent centromeres and letters represent genetic loci). Which of the aberrant forms represents duplication? Normal Chromosomes (A) (B) | (D) (E)

39 The structures labelled A and B in the image below represent: СТАААТСGGT. Allele for red flowers B Enzyme A Allele for white flowers One allele sufficient to ATAAATCGGT produce half the pigment Select one alternative: O the locus for flower colour; a red flower the locus for flower colour; a white flower O non-homologous chromosomes; a red flower O homologous chromosomes; a pink flower

Based on the attached image, identify the stage at which each cell is in and draw an animal cell with a diploid chromosome number of 6. Indicate maternally- & paternally-derived chromosomes as red and blue, respectively, in your diagram. You do not need to indicate any crossing over. Be sure to include any of the indicated labels.

Describe the characteristics that are used to classify and identify chromosomes?