Lab Practical 1

Question 1

What were the 5 purposes for the Cell Cycle & Mitosis lab (lab 1)?

Answer 1

• Know what happens during interphase, mitosis, cytokinesis
• Know the basic structure of eukaryotic chromosomes
• Know the chromosome movement of mitosis
• Know how DNA amount & chromosome number changes during a cell cycle
• Recognize phases of a cell cycle under microscope

Question 2

What are the 3 major events of the cell cycle?

Answer 2

• Interphase
• Mitosis
• Cytokinesis

Question 3

What is the purpose of Interphase of the Cell Cycle?

Answer 3

• It grows & performs regular maintenance

- This is where it replicates its chromosomes if it’s told to

Question 4

What is the purpose of Mitosis of the Cell Cycle?

Answer 4

-This is where the replicated chromosomes are moved around to make sure that the 2 daughter nuclei have the same number of chromosomes as original cell

Question 5

What is the purpose of Cytokinesis of the Cell Cycle?

Answer 5

-This is where the cytoplasm fully divides= creating the 2 daughter nuclei

Question 6

How does the Mitotic cell division serve a multicellular organism?

Answer 6

• It allows the creation of new cells so that it can become an embyro & beyond
• It also allows for replacement of dead/damaged cells

Question 7

What are the defining characteristic of Prophase?

Answer 7

-Chromosomes condense & mitotic spindle forms

Question 8

What are the defining characteristics of Prometaphase?

Answer 8

• Nuclear membrane breaks down

- Spindle connects to kinetochore & starts to pull towards metaphase plate

Question 9

What is the defining characteristics of Metaphase?

Answer 9

-Chromosomes are lined up at the metaphase plate

Question 10

What are the defining characteristic of Anaphase?

Answer 10

• Cohesion protein is dissolved
• Chromatids are pulled apart due to motor proteins moving along the kinetochore microtubules
• Once they are completely pulled apart they are 1 chromatid chromosomes

Question 11

What are the defining characteristics of Telophase?

Answer 11

• Nuclear membrane reforms around both groups
• As new nuclei form, chromosomes decondense
• Spindle apparatus disappears

Question 12

What is the defining characteristic of Cytokinesis?

Answer 12

• It occurs during telophase but ISN’T part of telophase

- 2 daughter nuclei are now independent

Question 13

What’s the difference between a 2 chromatid chromosome and a 1 chromatid chromosome?

Answer 13

-A 2 chromatid chromosome has twice the amount of genetic material as the 1 chromatid chromosome

Question 14

Where in the cell cycle does a cell have 2 chromatid chromosomes?

Answer 14

• G2
• Prophase
• Prometaphase
• Metaphase

Question 15

Where in the cell cycle does a cell have a 1 chromatid chromosome?

Answer 15

• G1
• Anaphase
• Telophase

Question 16

How much DNA does a cell have during the G1 phase?

Answer 16

It has 2C (how much DNA in a gamete)

Question 17

How much DNA does a cell have during the S phase?

Answer 17

-Since this is the time for replication, the cell grows from having 2C to 4C

Question 18

at what phases does a DNA cell have 4C DNA?

Answer 18

-During G2, prophase, prometaphase, anaphase, telophase

Question 19

What is the Mechanism for moving chromosomes in Mitosis?

Answer 19

-Via protein filaments (kinetochore microtubules) that attach to the kinetochore region of the centromere

Question 20

What is the role of Kinetochore Microtubules?

Answer 20

-They guide motor proteins that are located at the kinetochore to pull the sister chromatids apart during anaphase

Question 21

What is the mechanism that separates the sister chromatids?

Answer 21

-The kinetochore microtubules shorten while the motor proteins pull the chromosomes along the microtubules

Question 22

What is a Null Hypothesis?

Answer 22

• Says that there isn’t a difference between the means of 2 populations
• Any difference is due to chance

Question 23

What is an Alternative Hypothesis?

Answer 23

-Says that there is a difference between the means of the 2 population

Question 24

What would happen to the chromosome number if Meiosis did not occur?

Answer 24

-It would number each generation

Question 25

What do Genes contain?

Answer 25

-The info that cells use to guide the production of proteins

Question 26

What is a Locus?

Answer 26

-The particular location of a gene on a chromosome

Question 27

What are Alleles?

Answer 27

-They are the 2 genes found on corresponding loci on the homologous chromosomes

Question 28

What is a Centromere?

Answer 28

-It is the region where the spindle fibers attach

Question 29

What are Homologous Chromosomes?

Answer 29

- They are chromosomes that are the same size & shape | - They also have their loci in the same order

Question 30

What is a Genotype?

Answer 30

-It refers to the genetic composition of an organism

Question 31

What is a Wild Type?

Answer 31

- It is the standard type you'd find in the wild | - In the drosophila lab the wild/original type was a fly w/ tan body, smooth wings& red eyes

Question 32

What is the Wild Type in Drosophila?

Answer 32

Red eyes

Question 33

How do the movement of non-homologous chromosomes relate to the feature of the genetic model used in lab?

Answer 33

-The alleles controlling a particular trait move independently of alleles controlling other traits

Question 34

If you want to easily establish the dominance relationship between 2 alleles what must be true about their parent's cross?

Answer 34

- Both parents should be purebreds | - The trait that disappears in the F1 generation is a recessive allele

Question 35

When do you use a T-test?

Answer 35

-You use a T-test in scenarios where there's an average

Question 36

When do you use a X^2 test?

Answer 36

-You use a X^2 test in scenarios when trying to determine phenotypes and making sure that the model proportions are correct (greater than .05) or incorrect (less than .05)

Question 37

How do you do a T-test?

Answer 37

- You must remember the equation which is x2-x1/su - After you get your t-value you must figure out the degree of freedom which is the total amount of data points & subtract 2 - Now that you have the Degree of freedom and the t-value we go to the t-chart and see if you accept or reject the null hypothesis

Question 38

How do you know that you reject or accept the null hypothesis for a t-test?

Answer 38

- You reject it when the probability is UNDER .05 which means that there is strong evidence against the null hypothesis - You accept it when the probability is OVER .05

Question 39

How do you do a X^2 test?

Answer 39

- we use the formula (O-E)^2/ E - After getting the x^2 value we find the degree of freedom which is the number of categories minus 1 - Then using these 2 values you go to the x^2 chart and determine if you accept or reject the null hypothesis

Question 40

When do you reject/accept the null hypothesis for a x^2 test?

Answer 40

- If the probability value is UNDER .05 we reject the null hypothesis and say that the model proportions aren't correct - If the probability value is OVER .05 we accept the null hypothesis and say that the model proportions are correct

Question 41

What is the relationship between the phenotypic notations of mutant & wild type?

Answer 41

- Mutants and Wild type phenotypic letters are ALWAYS OPPOSITE - Mutants can have upper case & lowercase letters to show that it is dominant or recessive - Wild type can only have lowercase letters with a plus superscript

Question 42

What is a key concept about Wild type?

Answer 42

-THEY ARE NOT ALWAYS DOMINANT