Midterm Biology 2010
Prokaryotic cells do not contain:
1.membrane-bound 2.nucleus and whose structure is simpler compared with a eukaryotic cell
6. How is the substrate of an enzyme different from the active site?
Active site enzyme are present itself in Enzyme while substrate are another molecules which comes and held to active site and change to product. They are changeable while active site is not changeable acter the reaction. Substrate is consumed during the reaction. Substrate ---------Enzyme--> Product + enzyme.
Rod shape is known as : a.Round b.coccus c.bacillus d.spiral e.spirillum
Bacillus
1. Which feature is present in animal cells, but absent in plant cells? a. Centrioles b.Chloroplast c.Nucleus d.Cell wall
Centrioles
22. Describe the shape and the location of chloroplasts.
Chloroplasts are oval shaped the cytosol of a cell.
Round shape is known as : a.coccus b.rod c.bacillus d.spiral e.spirillum
Coccus
47.Given what you know about cyanide poisoning, do you think that giving a person oxygen would be an effective treatment? Why or why not? .
Giving a person oxygen would not be an effective treatment for cyanide poisoning. This is because the problem in cyanide poisoning is not lack of oxygen, but rather the inability of cells to utilize oxygen due to the inhibition of cytochrome c oxidase. Explanationfor step 2 Although oxygen may still bind to hemoglobin in the bloodstream, it cannot be used by cells to produce ATP in the absence of functioning cytochrome c oxidase.
· Rough endoplasmic reticulum
Location of protein synthesis, sorting, and packaging for secretion.
· Golgi apparatus
Location where proteins are modified, sorted, and packaged for secretion.
There are three factors that determine the quality of a microscopic image:
Magnification is the apparent increase in image size. Resolution is the ability to distinguish fine detail. Contrast refers to the ability to distinguish objects, such as cells, from the background.
17. If you're using the 40x objective and you know your ocular is 10x, what is the total magnification?
Objective = 40X Ocular = 10X If we calculate the total magnification we simply multiply the power of the objective lens with the magnification power of the ocular lens. So the total magnification is 40X × 10X = 400X
3.What was the optimal pH for catalase activity? Was the prediction you made correct?
Optimal PH for catalase activity is 7 and below this ph and above 7 it will decrease and affect the activities of catalase Enzyme.
Bacillus shape is known as : a.Round b.coccus c.Rod d.spiral e.spirillum
Rod
Coccus shape is known as : a.Round b.rod c.bacillus d.spiral e.spirillum
Round
· Centrioles
Site of microtubule growth in animal cells.
· Chloroplast
Site of photosynthesis in plants and other photosynthetic cells.
· Field of view
The visible portion of the slide through the eyepiece. The field of view will decrease as magnification increases.
28. What is the Biuret test detecting? Be as specific as possible.
· Proteins: ·peptide bonds.
10. What happens to enzymes exposed to very high temperatures?
· When the enzymes are exposed to very high Temperature, they get denatured.
8. Over what temperature range does catechol oxidase remain active?
·Catechol oxidase remains active from the temperature just above 0 degree centigrade to the temperature just below 100 degrees centigrade.
Plant cells will also contain structures that can help distinguish them from animal cells, such as:
1. Chloroplasts 2. cell wall 3. central vacuole.
Steps to preparing a wet mount slid
1. Collect sample (such as saliva, blood, other cells) and placed it on clean and dry slide. Sample should be very thin so we can view it properly. 2. Now add one drop of water over the sample. Make sure to add one drop only otherwise coverslip will float, and we won't be able to view sample. 3. Now place the coverslip over the sample by making angle of 45° so that we can avoid air bubbles under the coverslip. 4. Now slide is ready to be viewed.
Plant and animal cells contain several of the same organelles such as a:
1. Nucleus 2. Cytoplasm 3. Mitochondria 4. Cell membrane
Eukaryotic cells
1. membrane bound 2.nucleus and have a more complex structure with increased intracellular compartmentalization
Eukaryotic cells can be further classified as either:
1.protist 2.fungi 3.plants 4.animals.
11. If the enzymes work at 40° but not at 80°, and both have catechol ·
40° brown and 0 lighter because at 40° the enzyme is working at 80° no and if isn't you are not getting the hydroquinone.
13 What is the range of pH over which catechol oxidase catalyzes catechol to benzoquinone?
5-9
1.2 What is the optimum pH for the activity of catechol oxidase?
7(neutral)
31. What is the difference between a hypertonic solution and a hypotonic solution?
A hypertonic solution has a high solute concentration. hypotonic solution has a low solute concentration. When a cell is kept inside a hypertonic solution, it shrinks. Oppositely, a cell becomes turgid(swallen) when kept in the hypotonic solution.
25. The monomers that make up carbohydrates are:
A monosaccharide is the monomer that makes up a polysaccharide. In short- Monomer is a general term, while monosaccharide is a specific term for the monomer that makes up a carbohydrate. A monosaccharide is a single sugar molecule. This includes glucose, fructose, and galactose.
· Cell wall
A rigid structure located external to the cell membrane providing additional support. Found in most prokaryotes and plant cells while not a feature of animal cells.
34. Why are dehydrated patients given saline intravenously instead of water?
Because saline solution is precisely prepared to match the electrolytes found in blood plasma, it has a lower osmotic impact than other intravenous fluids. As electrolytes, it comprises sodium and chloride ions.
24. "Animal cells have mitochondria; plant cells have chloroplasts." Is this statement true or false? Explain. ·
Both animal and plant cells have mitochondria, but only plant cells have chloroplast.
5. What is the substrate for catalase? What are the products of the reaction?
Catalase is an enzyme which having hydrogen peroxide as a substrate. It's product are oxygen and water.
33. What will happen to animal cells placed in a hypotonic solution? Why should this be different from plant cells?
Cells Swell placed in a hypotonic solution will take in water across their membrane until both the external solution and the cytosol are isotonic. A cell that does not have a rigid cell wall, such as a red blood cell, will swell and lyse (burst) when placed in a hypotonic solution.
44. Recall your knowledge of the function of organelles. What function of the cells was interrupted in these patients?
Cellular Respiration (Mitochondria) The mitochondria is known as the powerhouse of the cell. It is responsible for the release of ATP energy.
Fields of study where a microscope is a necessary tool include:
Cytology - the study of cells. Histology - the study of tissues. Pathology - the study of disease.
· The advantages of a wet mount may include:
Fast preparation. · Requires no special equipment other than a transfer pipette, slide, and cover slip. · Organisms may be viewed in their living state. · Movement of motile microorganisms can be observed.
20. How do you make the image of the slide clear when viewing through the ocular lens?
First, focus the image using the coarse and fine focus adjustment while looking down through the eyepiece of the microscope.
The scientific method usually involves at least four main steps:
Hypothesis Experiment Analysis Conclusion
32 What will happen to plant cells that are placed in a hypertonic solution?
If a cell is placed in a hypertonic solution, water will leave the cell, and the cell will shrink.
7. The pH in the stomach is pH 2.0. What do you think the optimum pH is for pepsin, an enzyme that is secreted in the stomach?
If ph in stomach is 2 and pepsin work here, then definitely it will have optimal activity at this temperature so that this can effectively work here. · So optimum temperature for pepsin will be 2.
15. If you bump your microscope and lose focus, what do you do to refocus your specimen?
If we bump our microscope and lose its focus we should follow the steps for refocusing... I. 1st rotate to the lowest-power objective II. Put the slide on the stage and fix it with the stage clips. III. Use the coarse adjustment knob to observe the field and place the specimen in the center. IV. Then shift the objective with a higher power magnification. V. 5. then uses the fine adjustment knob for focusing. Now it is ready to observe the specimen under the microscope.
29. Each test included a sample that was just water. Why is it important to include a water-only sample for each test?
In order to achieve ultra-sensitivity, pure water is essential. It provides you with more control over the type of substances dissolved and the exact concentration of your solute, leading to higher experimental reproducibility.
· Mitochondrion
Location of adenosine triphosphate (ATP) synthesis.
· Smooth endoplasmic reticulum
Location of detoxification of chemical
· Nucleus
Location of most of a cell's deoxyribonucleic acid (DNA).
48.. Recall that the mitochondrion is sometimes called the "powerhouse" of the cell. What does this mean? Why is the mitochondrion important?
Mitochondria called as powerhouse of cell because it produces ATP which require fir cellular process. Mitochondria is important because it contain while electron transport chain which produce energy.
1. Were chloroplasts observed in the onion cells? Why or why not?
No, the chloroplasts don't show in onion cell. The bulb of an onion doesn't have chloroplasts because the bulb grows underground. Because the chloroplasts are used to create sugar in the presence of sunlight, these organelles are not needed · if they aren't going to be exposed to the sun. Instead, the onion grows using energy stores initially and then produces a stem. This greenery contains the only chloroplasts in the plant.
1. A mutation can reduce the amount of chlorophyll in the leaf. Would this also reduce the rate of photosynthesis? ·
No.This is because the amount of the chlorophyll; ls not a limiting factor of photosynthesis. · Explanation: · Generally, the three factors are regarded as the limiting factors of photosynthesis. These are the CO2 concentration, light intensity, and temperature. Fluctuations in the availability of these factors affects the rate of photosynthesis.
45. While poison is the main suspect in the case, what are other ways a person could die of hypoxia?
Other than poison, person could die by suffocation in which he did not get enough oxygen to breath. So cells of body need oxygen to live, if not they die.
You place spinach leaves in a sealed container and measure the rate of respiration. The leaves are not exposed to light; therefore, the level of oxygen does what over time? What about carbon dioxide?
Oxygen decreases carbon dioxide Increases
46.Analyze the oxygen levels of the victims. Were the levels higher or lower than normal? How can you reconcile this observation with the cause of death being hypoxia?
Oxygen level in blood is higher but there is not sufficient delivery of that oxygen to the tissue.
In what kind of cell is found the central vacuole?
Plant Cells
The spirillum shape is known as : a.Round b.coccus c.Rod d.spiral e.spiral
Spiral
The spiral shape is known as : a.Round b.coccus c.Rod d.spiral e.spirillum
Spirillum
19. Where do you place slides on microscopes for observations? In: this area moves up and down.
Stage Coarse Adjustment Knob- The coarse adjustment knob located on the arm of the microscope moves the stage up and down to bring the specimen into focus.
Place the steps to obtain a human cheek cell (buccal) smear in the correct order.
Step 1 : Using a sanitized toothpick gently scrape the inside of the cheek Step 2 : Smear the scrapings onto a clean, dry slide Step 3 : Add a single drop of stain to slide Step 4 : Cover with coverslip
35.Based on what you have observed, are the dialysis bags permeable to sucrose?
Sucrose would be too large to pass through the dialysis tubing, so the water in the beaker should not test positive for sugar in the end result.
27.Which test could you use to distinguish between diet and regular soda? What would the test detect?
Sugar or glucose test
· Central vacuole
The central vacuole is a membranous sac whose function is storage and cell volume regulation. Found in plant cells.
· Which choice chamber is the experimental group? a. The choice chamber with sand on both sides. b. The choice chamber with cornstarch on one side and sand on the other side.
The choice chamber with cornstarch on one side and sand on the other side.
· Cytoplasm
The components of a cell between the nucleus and cell membrane.
36. Do you have evidence that cell respiration occurred in peas? Explain.
The effect of temperature on the rate of cell respiration in peas is that the higher the temperature the higher the cell respiration. Low temperature slows down the enzymes causing the rate of cellular respiration to decrease.
1. What was the optimal temperature for catalase activity? Was the prediction you made correct?
The optimal temperature for catalase activity is 37° C(body temperature) and ph will be 7 . This prediction dependent on what variable factors are included.
9. What is the optimum (best) temperature for the activity of this enzyme?
The optimum temperature is 40 degrees centigrade.
18. Why is it important to begin focusing with the scanning objective?
To view a specimen under a microscope the 1st step is " focusing on scanning objective". The lens of the scanning objective magnifies 4x. It is the shortest objective. It is used to study a general overview of the specimen.
4..Can you identify any potential problems or sources of error with the experimental design? How could it be improved?
Variation in quantity of fluid deliver with pipette. Over saturation of substrate so that enzyme activity may give false indication.
41.What about a plant that exhibits variegation... Do areas of the leaf with chlorophyll outperform areas that lack chlorophyll? Could you design an experiment to test this?
Yes, the areas in the variegated leaf having chlorophyll outperform the areas that lack chlorophyll. This can be demonstrated be simple iodine test where we pour the iodine on the leaf. Non variegated portion will turn blue black which confirms the presence of starch there. This will indicate the photosynthesis.
15. Why must you center your image before switching to a higher objective?
You must have the object centered before you change objectives to increase the magnification, because the field of view becomes smaller; if the object is off to the side, it may disappear when you go to higher magnification.
Why was a stain added to the human epidermal cells from the cheek smear prior to microscopic observation?
a. The stain was used to add contrast and make the cells easier to view. b. The stain preserved the cells to allow for microscopy.
A controlled experiment
allows comparison between a control group and a test (experimental) group that has been exposed to an experimental factor (the variable)corn. In the analysis phase, the results of the experiment are examined for agreement with the hypothesis. Any differences that are observed between the two groups can be attributed to the effects of the experimental factor.
controlled experiment
allows scientists to test hypotheses and to draw conclusions based on reproducible results.
26. The monomers that makeup proteins are:
amino acids.
Why is it easier to locate your specimen at a lower power objective? a) The slide is brighter at a lower power objective. b) The lower power objective will have a greater field of view. c) The slide cannot be focused without first focusing on the lower power objective. d) The slide has greater contrast at a lower power objective.
b) The lower power objective will have a greater field of view.
The cell membrane (plasma membrane)
creates a barrier between the internal and external cellular environment and controls what can enter and leave the cell. Found in both eukaryotes and prokaryotes.
2. What happened to catalase activity at 80˚C? Based on what you know about protein structure, how would you explain that result?
fails to function because at higher temperatures they denatured as we know these enzymes are made of proteins, which have binding and they break that and disturbed it.
39. Why do germinating peas undergo(experience) cell respiration
germinating peas undergo cellular respiration as they need energy for growth and development.
Brightfield microscopes use a combination of
glass lenses and light to view the specimen.
30.What are other factors that can affect the rate of diffusion?
i. Temperature II. concentration gradient III. size of the molecule IV. presence of a membrane.
The conclusion
includes a representation of the results and a discussion regarding the confirmation or rejection of the original hypothesis.
A hypothesis
is a formulated statement of predicted behaviors
The scientific method
is a process that involves the formation and testing of hypotheses.
Resolution
is the ability to distinguish fine detail.
Magnification
is the apparent increase in image size.
The goal of microscopy
is to create a magnified image of objects too small to be seen with the eye alone.
43. List any factors that you think may affect the rate of photosynthesis. Consider environmental factors that you could manipulate during the lab. ·
light intensity · carbon dioxide concentration · temperature
· A disadvantage
of most stains is that they are toxic and used on dead cells and tissues. As a result, observation of cell behavior cannot be viewed.
· Stains are
often used to visualize cellular structures by enhancing contrast.
37. What is the effect of germination on the rate of cell respiration in peas?
peas undergo cellular respiration as they need energy for growth and development.
All cells can be classified as either
prokaryotic or eukaryotic
Contrast
refers to the ability to distinguish objects, such as cells, from the background.
There are 3 common shapes:
round (coccus). rod (bacillus). spiral (spirillum).
The lower the power objective
the greater the field of view.
38. What is the effect of temperature on the rate of cell respiration in peas?
the rate of cell respiration in peas is that the higher the temperature the higher the cell respiration. Low temperature slows down the enzymes causing the rate of cellular respiration to decrease.
42. In this experiment, the amount of oxygen produced was observed to measure the rate of photosynthesis. What else could you measure to determine the rate of photosynthesis?
the rate of oxygen output · the rate of carbon dioxide uptake · the rate of carbohydrate (glucose) production
Cytology a.the study of cells. b.the study of tissues. c.the study of disease.
the study of cells.
Pathology a.the study of cells. b.the study of tissues. c.the study of disease.
the study of disease.
Histology a.the study of cells. b.the study of tissues. c.the study of disease.
the study of tissues.
