Review for Biology Unit Test: The Microscope, Parts of the Cell, DNA, Mitosis and Cancer

ANSWER KEY

1. Define biology.The study of living organisms.

2. List 5 characteristics of living things.a) Living things are made of cellsb) Living things obtain and use energyc) Living things moved) Living things grow and develope) Living things reproduce f) Living things respond to their environmentg) Living things adapt to their environment

You could use any of these 5

3. How is a robot like a living thing? In what three ways are robots not like living things?

Similarities Differences- Robots use energy- Robots move- Robots respond to their environment

- Not made of cells- Does not grow and develop- Does not reproduce- Does not adapt to environment

4. What are the 3 main statements of the Cell Theory?a) All known living things are made up of one or more cellsb) All living cells arise from pre-existing cells by divisionc) The cell is the fundamental unit of structure and function in all living organisms

5. Know the parts of a compound light microscope and their functions.

6. Using the compound light microscope:a) describe how to focus the microscope, beginning with low power and working up to high power.

i. Turn the revolving nosepiece to the low power objective lensii. Look at the objective lens and stage from the side and turn the coarse adjustment

so that the stage moves upward. Move the stage as far as it will go without letting the objective lens touch the cover slip

iii. Look through the eyepiece and move the fine adjustment knob until the image comes into focus

iv. With the image in focus you may now switch to the medium power objective lens and bring the image into focus using the fine adjustment knob. Once the image is focused you can switch to the high power objective lens.

b) why should the coarse adjustment knob not be used with the high power objective lens?i. Because the coarse adjustment knob moves the stage in large increments not

suitable for the high power objective lens. Furthermore you risk damaging the lens if it comes in contact with the cover slip.

c) describe how to correctly prepare the microscope for storage.i. Turn the microscope off

ii. Clean the microscope surfaces except for the lenses. iii. Turn the revolving nosepiece so that the low power objective lens is selected. iv. Move the stage down using the coarse adjustment knobv. Cover the microscope with a plastic microscope cover

Write the number of the part of the light microscope beside the name of this part:

2 arm

10 base

8 coarse adjustment (focus)

7 fine adjustment (focus)

9 light source

4 objective lens

1 ocular lens

3 revolving nosepiece

6 stage

5 stage clip

d) if you look at the letter “f” under the microscope, sketch what the image would look like.

e) compare the amount of detail you see under low and high magnification.i. Low power magnification allows you to view multiple cells and features such as

cell membrane.ii. High power magnification allows you to view individual cells and more detailed

features such as the nucleusf) compare the amount of the specimen you see under low and high magnification.

i. Under low power you will see multiple cellsii. Under high power you will see only a few (or less) cells.

g) if the ocular lens is 8x magnification and the objective lens is 20x, what is the total magnification?

8 x 20 = 160x

7. Know how to prepare a wet mount:a) what is a “mounting medium” and why is it used (2 functions)?

A mounting medium is the solution used to hold a specimen. It is placed between the slide and the cover slip.

Functions: i. Allows you to view live specimens. ii. Holds the specimen in place for viewing. iii. Can be used to make permanent slides in which the mounting medium hardens.

b) what mounting medium (stain) did we use for cheek cells? for onion cells?Cheek Cells: Methylene Blue stain in a Glycerine mounting mediumOnion Cells: Safranin stain in a Glycerine mounting medium

c) why should you hold the coverslip by the edges?To prevent oils from your hand (fingerprints) from getting on the slide and interfering with the image seen through the microscope.

d) why is the coverslip lowered slowly and at a 45° angle over the specimen?This helps prevent bubbles from forming between the cover slip and the mounting medium.

e) describe the steps to prepare a wet mount of either a human epithelial cell or an onion epithelial cell. Include the name of the mounting medium used.

Human epithelial cell:

a) Gently scrape the inner side of the cheek using a toothpick, which will collect some cheek cells.

b) Place the cells on a glass slide that has water on it.c) Mix the water and the cheek cells using a needle and spread them.d) Take a few drops of Methylene blue solution using a dropper and add this to the

mixture on the slide.e) After 2-3 minutes remove any excess water and stain from the slide using  a blotting

paper.f) Take a few drops of glycerine using a dropper and add this to the mixture.g) Take a clean cover slip and lower it slowly, and at a 45o angle, onto the mixture with

the aid of a needle.h) Using a brush and needle, press the cover slip gently to spread the epithelial cells.i) Remove any extra liquid around the cover slip using a blotting paper.j) Place this glass side on the stage of the compound microscope and view it.

Onion Epithelial Cell:

a) Pour some distilled water into a watch glass.b) Peel off a leaf from half a piece of onion and using the forceps, pull out a piece of

transparent onion peel (epidermis) from the leaf.c) Put the epidermis in the watch glass containing distilled water.d) Take a few drops of safranin solution in a dropper and transfer this into another

watch glass.e) Using a brush, transfer the peel into the watch glass containing the safranin solution.f) Let this remain in the Safranin solution for 30 seconds, so that the peel is stained.g) Take the peel from the Safranin solution using the brush and place it in the watch

glass containing the distilled water.h) Take a few drops of glycerine in a dropper and pour 2 - 3 drops at the center of a dry

glass slide.i) Using the brush, place the peel onto the slide containing glycerine.j) Take a cover slip and place it gently on the peel with the aid of a needle.k) Remove the extra glycerine using a blotting paper.l) Place this glass side on the stage of the compound microscope and view it.

8. What parts of plant and animal cells can you see under a light microscope?

Animal Cells: cell membrane, nucleus, cytoplasm

Plant Cells: cell membrane, cell wall, cytoplasm, chloroplasts, vacuole, nucleus

9. Know the parts of plant and animal cells as seen through an electron microscope. Know the function of each of these parts. Practice by covering up the “Function” side of the chart on the homework page “Cell Organelles and their Functions”.

10. Know how different organelles are related to protein production in the cell.

Ribosomes are the site of protein production. Some float freely in the cytoplasm and others are attached to the endoplasmic reticulum.

The endoplasmic reticulum transports proteins.

The Golgi body packages and sorts proteins for transport out of the cell.

Write the number of the part of the animal cell beside the name of this part:

__1___ cell membrane

__7___ centrioles

__2___ chromatin

__4___ endoplasmic reticulum

__5___ golgi apparatus

__8___ lysosome (vesicle)

__6___ mitochondria

__3___ nucleolus

__9___ ribosomes

Write the number of the part of the plant cell beside the name of this part:

___2__ cell membrane

___1__ cell wall

___3__ central vacuole

___4__ chloroplast

___7__ chromatin

___6__ endoplasmic reticulum

___5__ mitochondria

___8__ nucleolus

___9__ ribosomes

11. Know the names of two different types of proteins and where each is found in the body.

Hormones: Chemical messengers carried through the blood

Enzymes: Work to accelerate chemical processes in the body such as digestion.

Structural (fibrous) Proteins: Form bones, muscles, tendons, skin, and cartilage.

Antibodies: Formed in white blood cells and attack bacteria and viruses (foreign invaders)

Storage Proteins: Store minerals such as potassium and iron

Transport Proteins: Carry vital materials to the cells such as oxygen which is carried by hemoglobin.

12. What process takes place in chloroplasts? What green pigment allows this to happen?

Photosynthesis, Chlorophyll

13. What process takes place in mitochondria? Do plants cells have mitochondria? Why or why not?

Cellular respiration occurs in the mitochondria. Yes plants have mitochondria. They require mitochondria to convert the sugars they produce during photosynthesis into the energy they require.

14. Complete the Venn diagram to compare plant and animal cells. The similarities go in the centre where the 2 circles overlap.

Both:- Cytoplasm- Endoplasmic

reticulum- Ribosomes- Mitochondria- Golgi Body- Cell membrane- Microtubules- Nucleus

Animal Cells:- Round (irregular

shape)- One or more small

vacuoles- Centrioles- Lysosomes

Plant Cells:- Cell wall- Rectangular (fixed

shape)- Large central

vacuole- Chloroplasts

DNA1. Label the molecule of DNA:

2. “A” stands for __Adenine__, it always bonds with __Thymine__ ( T ).

“G” stands for __Guanine__, it always bonds with __Cytosine__ ( C ).

3. If 22% of the nitrogen bases in a strand of DNA is guanine, calculate the percentages of the other nitrogen bases.

22% Guanine therefore 22% Cytosine

28% Adenine and 28% Thymine

4. When is DNA found as chromatin? When is DNA found as chromosomes? Why is DNA found as chromosomes during this time?

DNA is found as chromatin during interphase when the cell is undergoing growth

DNA is found as chromosomes during cell division

DNA is packaged into chromosomes during cell division to allow for the movement and division of the genetic material into the two daughter cells

5. Using your notes from class, complete the following statements about DNA:a) DNA is found in the __Nucleus__ of the cell.b) DNA stands for __Deoxyribonucleic Acid__.c) DNA contains three types of molecules: __Phosphate__, __Deoxyribose Sugar__ and __nitrogenous

base__(A, T, C, G).d) The shape of a DNA molecule is a called a __Double Helix__.e) DNA carries the “recipes” for the cells to make its __Proteins__.f) When the genetic material is found as long thin strands of DNA it is called __Chromatin__.g) When the genetic material is coiled into shorter thicker “rods”, they are called __Chromosomes__.h) The recipe for a single protein is called a __Gene__.i) Before cell division, the DNA must be __Replicated __ (copied exactly).

Proteins1. Cells can be described as small factories that make __Proteins__.2. The “recipes” for ALL of a cell’s proteins are carried in the __DNA__.3. The “recipe” to make ONE single type of protein is called a __Gene__.

4. The organelles in the cell that make the proteins are called __Ribosomes__.5. The organelle in the cell that transports the proteins is called __Endoplasmic Reticulum__.6. The organelles in the cell that package the proteins are called __Golgi Bodies__.7. The organelles in the cell that store the proteins are called __Vacuoles__.8. What are five examples of proteins in your body? See number 11 Above

The Cell Cycle1. How do cells obtain their nutrients?

Cells obtain their nutrients through diffusion.

2. Why is it important that cells not get too large? If a cell becomes too large the surface area to volume ratio decreases and the cell cannot pass all of the nutrients and wastes in and out of the cell.

3. What are four reasons that cells divide?i. Reproduction (single celled organisms)ii. Growth/Repairiii. Increase surface to volume ratioiv. Differentiation (specializing into new tissues)

4. What are the two parts of the cell cycle?Interphase and Mitosis

5. What happens during interphase? What happens at the very end of interphase?During interphase cells grow. At the end of interphase cells replicate their DNA in preparation for mitosis.

6. What two types of cells in your body spend the longest time in interphase? Nerve and Muscle

7. What two types of cells in your body divide very frequently?Mucosal (mucus) and Epithelial (skin)

8. Outline, in order, the four steps that take place when DNA is replicated.i. DNA unwindsii. Strands of DNA are separated “Unzipped” by breaking the hydrogen bonds.iii. New nucleotides are paired with each strandiv. The two new strands are wound up

9. Give two reasons why the structure of the DNA molecule is so well suited to its function.i. As a double helix DNA can be broken into two complimentary strandsii. Complimentary bases are hydrogen bonded allowing the strands of DNA to be separated.

10. What happens during mitosis?A cell divides into two equal parts

11. What is the function of centrioles? Do plant cells have centrioles? Animal cells?Centrioles form spindle fibres which separate chromosomes during cell division. Plant cells do not have centrioles. They have tubulin which serves a similar function. Animal cells do have centrioles.

12. What happens during cytokinesis? How is cytokinesis different in plant and animal cells?Cytokinesis is the process by which a cell completes its division into two daughter cells. In animal cells the cell “pinches” the membrane until the cell divides into two. In plant cells a cell plate forms in the middle of the cell effectively dividing the cell into two compartments. These two cells can then complete separation.

13. What happens in prophase and how can you recognize this stage in a diagram?During prophase the chromosomes become visible, the nuclear membrane begins to break down, the nucleolus disappears, centrosomes begin to move to poles, and spindle fibres begin to form.

14. What happens in metaphase and how can you recognize this stage in a diagram?Centrosomes arrive at poles, chromosomes align at the centre of the cell, spindle fibres attach to centromeres.

15. What happens in anaphase and how can you recognize this stage in a diagram?Chromatids separate and are moved to the poles by retracting spindle fibres.

16. What happens in telophase and how can you recognize this stage in a diagram?Spindle fibres start to disappear, nucleolus appears in each cell, nuclear membranes form, and chromosomes begin to uncoil becoming harder to see.

17. Identify the following stages of the cell cycle. Starting with interphase (#1), write a number in the top left-hand corner of each square to indicate the order that the steps take place. Label the significant structures. How can you recognize each stage?

Cancer1. Be able to recognize the definitions for the following terms for match-up or multiple choice questions:

tumour, cancer, mutation, carcinogen, benign tumour, malignant tumour and metastasis. Tumour: a swelling of a part of the body, generally without inflammation, caused by an abnormal growth of tissueCancer: the disease caused by an uncontrolled division of abnormal cells in a part of the bodyMutation: the changing of the structure of a geneCarcinogen: a substance capable of causing cancer in living tissue.Benign Tumour: A benign tumor is a mass of cells (tumor) that lacks the ability to invade neighboring tissue or metastasize.Malignant Tumour: A malignant tumor is a mass of cells (tumor) that is able to invade neighboring tissue or metastasize.Metastasis: the development of secondary malignant growths at a distance from a primary site of cancer.

2. Are all tumours cancer? Explain why or why not.No not all tumours are cancerous. Benign tumours are not considered cancerous as they cannot invade neighbouring tissue or metastasize.

3. What is the difference between a benign tumour and a malignant tumour?Benign Tumour: A benign tumor is a mass of cells (tumor) that lacks the ability to invade neighboring tissue or metastasize.Malignant Tumour: A malignant tumor is a mass of cells (tumor) that is able to invade neighboring tissue or metastasize.

#1 Interphase

-Nuclear membrane present. -DNA exists as chromatin

#2 Prophase

-Centrosomes moving to poles -DNA exists as chromosomes

#3 Metaphase

-Centrosomes align at centre of cell-Spindle fibres attach to centromeres

#4 Anaphase

-Chromatids moving to poles-Spindle fibres retracting

#5 Telophase

-Nuclear membrane reforming-Chromosomes begin to unwind

#6 Cytokinesis

-Cell division completes.-Two daughter cells formed

4. What are the three types of carcinogens? Give an example for each.Physical: such as ionizing radiation from UV or X-raysChemical: such as arsenic in cigarettesBiological: such as the HPV virus

5. What ways can a mutation happen? Describe what happens in each.i. Duplication: an extra copy of the gene is made and inserted into the chromosome.ii. Deletion: a gene, or part of a gene, is not copied so it is missing from the chromosome.iii. Insertion: a gene, or part of a gene, is inserted into a chromosome where it does not belong. iv. Inversion: genes, or parts of genes, are inserted into a chromosome backwards.

6. Do all mutations cause cancer? Explain why or why not.No. Mutations can occur in areas of the DNA which do not code for anything, or in a gene which is not being expressed (isn’t turned on), and mutations may even be beneficial.

7. What are the four stages of cancer? What happens in each stage?i. Stage 0: The cancer is still located in the place it started and has not invaded any nearby

tissues.ii. Stage I: A small tumour that has not grown deeply into nearby tissues and has not spread to

the lymph nodes or other parts of the body. iii. Stage II and III: Tumours which are larger in size, have grown deeply into nearby tissues,

and have spread to the lymph nodes, but not other parts of the body. iv. Stage IV: The cancer has spread to other organs of the body.

8. What happens during metastasis? Why is this bad?During metastasis the cancer travels to other locations in the body. This is bad because it makes fighting the cancer much more difficult and increases the chances that tumours will form in critical organs and body systems.

9. What are six differences between healthy cells and cancer cells?

Healthy Cells Cancer Cellsi. Grow and divide controllablyii. Organized arrangement of cellsiii. Have consistent cell shapeiv. Have normal sized nucleiv. Have one nucleusvi. Undergo programmed mitosis

- Grow and divide uncontrollably- Often crowd together - Are large and have irregular shapes- Have large, dark staining nuclei- Have more than one nucleus per cell- Undergo frequent abnormal mitosis

10. What is chemotherapy and how does it work? Why does it cause people to get sick and their hair fall out?Chemotherapy is the use of drugs to slow down or stop cell division. Chemotherapy targets cells which divide rapidly. This includes both normal (stomach, intestines, hair follicles, blood) and cancer cells. The loss of good cells causes people to become ill and lose their hair.

11. What is radiation therapy and how does it work?Radiation therapy uses high energy waves to kill rapidly dividing cells. The radiation damages the cell’s DNA preventing it from dividing properly, so it dies.