Ch 10 biology test

Ch 10 biology test DEFAULT

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One of the major goals of dividing cells is to split up their DNA as perfectly as possible. (Incorrect division of DNA = chance of a nonfunctional cell, or even cancer!) Learn how DNA combines with proteins to form chromosomes, why different types of cells have different chromosome numbers, and what the parts of a chromosome are.
Imagine scraping your elbow. Ouch! In addition to being a little uncomfortable, you just lost a bunch of skin cells. How does your body make new cells to replace ones that are damaged or lost? Some of the remaining cells can divide (undergo mitosis) to produce new, healthy replacement cells. Learn more about mitosis and how cells divide.
Level up on the above skills and collect up to 200 Mastery points
Normal human body cells have two complete sets of chromosomes, while sperm and egg cells have just one set each. How, then, does a normal body cell give rise to sperm or eggs? The answer lies in a two-step division process called meiosis. Learn more about meiosis and how it contributes to genetic variation in humans (and other sexually reproducing organisms).

Practice

  • MeiosisGet 3 of 4 questions to level up!
Cells in your body are dividing all the time. If they're healthy cells, they divide in a carefully controlled way, proceeding with division only when conditions are right. Cancer cells, on the other hand, divide in an uncontrolled way. Learn more about cell cycle control, cancer cells, and stem cells.
Level up on the above skills and collect up to 300 Mastery points
Level up on all the skills in this unit and collect up to 500 Mastery points!

About this unit

This unit is part of the Biology library. Browse videos, articles, and exercises by topic.
Biology is brought to you with support from the Amgen Foundation
Biology is brought to you with support from the
Sours: https://www.khanacademy.org/science/biology/cellular-molecular-biology

BIOLOGY
by Miller & Levine

[complete Table of Contents]

Use the pull-down menu to jump to any of the Book's 40 Chapters:

Additional Resources:

Stem Cells: Promises and Problems (Page 253)

What's your opinion on the controversial issue of embryonic Stem Cell research? Check out the "Issues" Feature on stem cells from page 253 of the Dragonfly book.

Mitosis - Animated

An animation showing the major events during mitosis in animal cells.

The Cell Cycle

An animated explanation of events during the phases of the cell cycle.

Chapter 10
Cell Growth & Division

In this chapter, students will read about the importance of cell division and the processes by which it occurs, with an emphasis on mitosis in eukaryotes. They will also read about the cell cycle and its control mechanisms.. The links below lead to additional resources to help you with this chapter. These include Hot Links to Web sites related to the topics in this chapter, the Take It to the Net activities referred to in your textbook, a Self-Test you can use to test your knowledge of this chapter, and Teaching Links that instructors may find useful for their students.



Section 10-1: Cell Growth
The larger a cell becomes, the more demands the cell places on its DNA and the more trouble the cell has moving enough nutrients and wastes across the cell membrane.

Section 10-2: Cell Division
During the cell cycle, a cell grows, prepares for division, and divides to form two daughter cells, each of which then begins the cycle again.
Biologists divide the events of mitosis into four phases: prophase, metaphase, anaphase, and telophase.
During prophase in animal cells, the centrioles separate and take up positions on opposite sides of the nucleus.
During metaphase, the chromosomes line up across the center of the cell. Microtubules connect the centromere of each chromosome to the poles of the spindle.
During anaphase, the centromeres that join the sister chromatids split, allowing the sister chromatids to separate and become individual chromosomes.
In telophase, the chromosomes, which were distinct and condensed, begin to disperse into a tangle of dense material.
Cytokinesis is the division of the cytoplasm.

Section 10-3: Regulating the Cell Cycle
Cyclins regulate the timing of the cell cycle in eukaryotic cells.
Cancer cells do not respond to the signals that regulate the growth of most cells. As a result, they form masses of cells called tumors that can damage the surrounding tissues.

Sours: http://www.millerandlevine.com/chapter/10/index.html
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Welcome to Class 11 Biology Chapter 10: Cell Cycle And Cell Division online MCQ Test. Students can take this free online test and practice the concepts they have learned while studying this chapter. This mock test and other such tests available on this website are free of cost and students can practice them as many times as they want.

Online Test For Class 11 Biology Cell Cycle And Division


General Instructions

  1. Your test contains multiple-choice questions with only one answer type questions. There are a total of 20 questions
  2. This is a 10 min test. Please make sure you complete it in stipulated time
  3. You can finish this test any time using the 'Submit' button.
This Online Test must be completed in 15 minutes.

900

General Instructions

  1. Your test contains multiple-choice questions with only one answer type questions. There are a total of 20 questions
  2. This is a 10 min test. Please make sure you complete it in stipulated time
  3. You can finish this test any time using the 'Submit' button.

 


Sours: https://physicscatalyst.com/testprep/class-11-biology/cell-cycle-and-cell-division-online-mcq-test/

Very Short Answer Questions.  (1 Mark)

1. How does a small amount of curd added to fresh milk convert it into curd? Mention a nutritional quality that gets added to the curd.

Ans: In a small amount of curd, a huge number of lactic acid bacteria can be detected. By creating lactic acid, proliferate and turn the milk into curd. Increased Vitamin B12 enhances nutritional quality.

2. Why is the secondary treatment of water in sewage treatment plants called biological treatment?

Ans: Organic wastes from sewage water are digested by particular bacteria in this treatment In the presence of water, microorganisms.

3. An antibiotic called Wonder Drug was used to treat the wounded soldiers of America during World War II. Name the drug and the scientist who discovered it.

Ans: Alexander Fleming invented penicillin.

4. You have observed that fruit juice in bottles bought from the market is clearer as compared to those made at home. Give a reason.

Ans: Pectinase and proteases are used to clarify bottle juices.

5. Alexander Fleming discovered Penicillin, but its full potential as effective antibiotic was established by other scientists. Name the two scientists.

Ans: Howard Florey and Ernest Chain were the two scientists. 

6. Name the plant whose sap is used in making Toddy. Mention the process involved in this.

Ans: The sap of a palm tree is used in making Toddy and the process is called fermentation.

7. What is the medical use of cyclosporin A.

Ans: During organ transplantation, cyclosporin A is used as an immunosuppressive drug.

8. Name the pests that ladybird & dragonflies help to get rid of respectively?

Ans: Aphids are controlled by ladybird beetles, and mosquitoes are controlled by dragonflies.

9. Give an example to prove that microbes release gases during metabolism?

Ans: Bread and Puffed dough are suitable examples of bacteria releasing gases during metabolism.

10. What are interferons?

Ans: The Interferons are those proteins that are released by the cells in response to the viral infection and it helps in the fight against viral infection.

11. Name the enzyme which is used as a clot buster" to remove a blood clots from the blood vessels of patients.

Ans: Streptokinase is used. 

14. Expand LAB?

Ans: Lactic acid Bacteria is the full form of LAB.

15. Name any two free-living nitrogen-fixing bacteria.

Ans: Two free-living nitrogen bacteria are Azotobacter, Azospirillum

16. Name the organism used in the dough for making bread.

Ans: Saccharomyces cerevisiae.

17. Name the fungus used as a biocontrol of plant diseases.

Ans: The fungus used as a biocontrol of plant diseases is known as  Trichoderma.

18. Name any two gases produced during secondary treatment of Sewage?

Ans: Methane, Hydrogen sulphide & carbon dioxide.

 

Short Answer Questions (2 Marks)

1. Name two alcoholic drinks produced in each of the following ways.

(i) by distillation and (ii) without distillation.

Ans:

(i) Distillation produces whisky, brandy, and rum.

(ii) Wine and beer that has not been distilled.

2. Lactic Acid Bacteria (LAB) is commonly used in the conversion of milk into curd. Mention any two other functions of LAB that are useful to humans.

Ans:

(i) Vitamin B12 is synthesised by LAB in the human gut.

(ii) The presence of LAB in the human stomach inhibits the growth of dangerous microorganisms.

3. How do mycorrhizae function as biofertilizers? Explain with examples.

Ans: Fungi connected with plant roots are known as mycorrhizae. Mycorrhizae are formed by many species of the Glomus genus. These fungal symbionts collect water and minerals such as phosphorus from the soil and pass them on to the plant.

Short Answer Question (3 Marks)

1. Fill in the blanks spaces a, b, c, d, e, and given in the following table:

S.No

Name of Organism

Commercial product

Use

1

Pencilliumnotatum

Penicillium

(a)

2

(b)

Lactic acid

Making curd

3

Streptococcus

Clot buster enzyme

(c)

4

Trichodermapolysporum

(d)

Immunosuppressive agent

5

Saccharomyces cerevisiae

Ethanol

(e)

6

(f)

Swiss cheese

Food Product

Ans: (i) to kill disease-causing bacteria

(b) Lactobacillus

(c) remove clots from blood vessels

(d) Cyclosporin A

(e) Beverage/medicines

(f) Propionibacterium Shermanii.

2. What is the biochemical oxygen demand (BOD) test? At what stage of Sewage treatment this test is performed? The BOD level of three samples of water labelled as A, B and C are 30 mg/L, 10mg/L and 500 mg/L respectively. Which sample of water is most polluted?

Ans:

  • The BOD test determines how quickly microorganisms in a sample of water absorb oxygen.

  • Secondary treatment or biological treatment.

  • Sample C is the most polluted of the three water samples since it has the greatest BOD level.

3. Given below is the Flow chart of Sewage treatment. Fill in the blank spaces marked

'a' to f.

(Image will be uploaded soon)

Ans:

(a) Primary treatment.

(b) Aeration

(c) Flocs 

(d) Biochemical Oxygen Demand (BOD)

(e) Activated sludge 

(f) Water bodies like river streams.

4. What are biofertilizers? A farmer is advised to add a culture of bacterium in the soil before sowing the crop. Name the bacterium in the culture. How is this bacterium useful to the crop?

Ans: Some points on biofertilizers are: 

  •  Biofertilizers are organisms that improve the soil's nutrient quality.

  • Azotobacter/Azospirillum is a bacteria found in the bacterium Azotobacter/Azospirillum (free living)

  • This bacterium converts atmospheric nitrogen into organic molecules that are used as a fertiliser by plants.

5. What are statins? Name the microorganism that produces this substance. How is it medically important?

Ans: The Monascuspurpureus produces statins, which are cholesterol-lowering drugs (Yeast). They operate as blood cholesterol-lowering drugs by competitively blocking the enzymes involved in cholesterol production.

6. Describe the procedure involved in Sewage treatment?

Ans: The following technique is performed for the treatment of sewage waste:

i) PRIMARY TREATMENT: This entails physically separating suspended materials in settling tanks in order to reduce BOD. The raw sewage is routed into massive open tanks where it is subjected to anaerobic digestion to remove the solid fraction.

ii) SECONDARY Therapy - Secondary treatment relies on microbial activity, either aerobic or anaerobic. Secondary treatment techniques include:

  1. Sand filters for filtration

  2. Process of aeration

  3. Application of oxidation ponds:

After drying, the sludge that collects after secondary treatment is disposed of, and the efferent is allowed to be used for tertiary treatment.

iii) TERTIARY TREATMENT: This treatment comprises chemical treatment to eliminate inorganic chemicals as well as pathogenic microorganisms. Chlorination is the most common disinfection procedure.

7. What is Biogas? How is it produced & Name the microbes invaded in Biogas production?

Ans: Biogas is the gas produced by anaerobic fermentation of waste biomass. It is made up of methane, CO2, hydrogen, nitrogen, oxygen, and hydrogen sulphide, among other things. Microbes that are often employed in the production of biogas-

i) hydrolytic bacteria, such as cellulosomes, clostridium, etc.

ii) Bacteria that produce hydrogen sulphide, such as Syntrophomonas wolfei

iii) Methanobacterium Omelianskii is an example of a methanogenic bacteria.

The biogas plant is fed by a concrete tank. The slurry is covered with a floating cover, which continues to rise when gas is created in the tank owing to microbial activity. The biogas plant includes an output that connects to a pipe that distributes biogas to surrounding residences. Microbes transform the organic part of biodegradable organic solid waste and trash into energy in the form of biogas and humus during biogas production.

CO + H₂O → CO₂ + H₂

CO₂ +4H₂ → CH4 + 2H₂O

CH3OH → CH4 +  02

8. Microbes can be used to decrease the use of chemical fertilizers & pesticides. Explain how this can be accomplished?

Ans: Chemicals are used to combat plant diseases and pests in modern society, however, these chemicals are poisonous and exceedingly damaging to humans and the environment. In agriculture, for example, there is a form of pest control that depends on natural predation rather than pesticides, such as To control butterflies, caterpillars, and other insects, a bacteria are known as Bacillus thuringiensis (Bt) is provided as dried spores in sachets that are mixed with water and sprayed onto sensitive plants such as brassicas, where the larvae are consumed. The toxin is released in the intestines of larvae, killing them. The bacterial sickness kills the caterpillar but does not harm other insects.

9. How do Bio fertilisers enrich the fertility of soil? How do cyanobacteria act as biofertilizers?

Ans: Microorganisms employ biological channels to improve soil fertility for optimal crop development, and they are referred to as "BIOFERTILIZERS." These microorganisms can boost crop output in one of two ways.

i) By removing nitrogen from the atmosphere

ii) Insoluble fertiliser solubilization

iii) By promoting the growth of plants.

iv) Through phosphorus absorption.

v) By allowing plant remnants to decompose.

Anabaena, a cyanobacterium found in the leaf cavity of the water fern Azolla, fixes nitrogen from the air and excretes nitrogenous compounds into the leaf cavity.

10. How does primary sludge differ from activated sludge? What type of changes in the sludge is carried out in an anaerobic sludge digester? Give the composition of biogas produced in the sewage treatment plant.

Ans: Primary sludge is made up of all solids, such as soil and small stones, that settle in the settling tank during sewage treatment. The sediment of bacterial flocs in the settling tank following biological treatment is known as activated sludge. Slime and fungal filaments bind bacteria together to form flocs. A portion of the activated sludge is used as inoculum in the aeration tank, and the rest is sent to the anaerobic sludge digester, which is a big tank. Other bacteria that grow anaerobically in this tank consume the bacteria, fungus, and cellulose in the sludge.

Biogas is a mixture of methane, hydrogen, and carbon dioxide created in sewage treatment plants.

Sours: https://www.vedantu.com/cbse/important-questions-class-12-biology-chapter-10

10 test ch biology

Review Questions

1.

A diploid cell has how many times the number of chromosomes as a haploid cell?

  1. four times
  2. half
  3. one-fourth
  4. twice
2.

The first level of DNA organization in a eukaryotic cell is maintained by which protein?

  1. cohesion
  2. condensin
  3. chromatin
  4. histone
3.

What inherited feature, in specific combinations, determines an organism’s traits?

  1. cell membranes
  2. genes
  3. proteins
  4. RNA
4.

What are identical copies of chromatin held together by cohesin at the centromere called?

  1. histones
  2. nucleosomes
  3. chromatin
  4. sister chromatids
5.

Chromosomes are duplicated during what stage of the cell cycle?

  1. \text{G}_1 phase
  2. prophase
  3. pro-metaphase
  4. S-phase
6.

Which of the following events does not occur during some stage of interphase?

  1. DNA duplication
  2. increase in cell size
  3. organelle duplication
  4. separation of sister chromatids
7.

Attachment of the mitotic spindle fibers to the kinetochores is a characteristic of which stage of mitosis?

  1. anaphase
  2. prophase
  3. prometaphase
  4. metaphase
8.

The fusing of Golgi vesicles at the metaphase plate of dividing plant cells forms what structure?

  1. actin ring
  2. cell plate
  3. cleavage furrow
  4. mitotic spindle
9.

What would be the outcome of blocking the S phase of interphase?

  1. The cell would enter karyokinesis.
  2. DNA replication would not occur.
  3. Centrosomes would be duplicated.
  4. The cytoskeleton would be dismantled.
10.

At which of the cell cycle checkpoints do external forces have the greatest influence?

  1. \text{G}_1 checkpoint
  2. \text{G}_2 checkpoint
  3. M checkpoint
  4. \text{G}_0 checkpoint
11.

If the M checkpoint is not cleared, what stage of mitosis will be blocked?

  1. prophase
  2. prometaphase
  3. metaphase
  4. anaphase
12.

Which protein is a positive regulator that phosphorylates other proteins when activated?

  1. p53
  2. retinoblastoma protein (Rb)
  3. cyclin
  4. cyclin-dependent kinase (Cdk)
13.

Which negative regulatory molecule can trigger apoptosis if vital cell cycle events do not occur?

  1. p53
  2. p21
  3. retinoblastoma protein (Rb)
  4. cyclin-dependent kinase (Cdk)
14.

What is the main prerequisite for clearance at the \text{G}_2 checkpoint?

  1. The cell has a reached a sufficient size.
  2. The cell has an adequate stockpile of nucleotides.
  3. An accurate and complete DNA replication has occurred.
  4. Proper attachment of mitotic spindle fibers to kinetochores has occurred.
15.

What do you call changes to the order of nucleotides in a segment of DNA that codes for a protein?

  1. proto-oncogenes
  2. tumor suppressor genes
  3. gene mutations
  4. negative regulators
16.

Human papillomavirus can cause cervical cancer. The virus encodes E6, a protein that binds p53. Based on this fact and what you know about p53, what effect do you think E6 binding has on p53 activity?

  1. E6 activates p53.
  2. E6 protects p53 from degradation.
  3. E6 mutates p53.
  4. E6 binding marks p53 for degradation.
17.

What is a gene that codes for a positive cell cycle regulator called?

  1. kinase inhibitor
  2. oncogene
  3. proto-oncogene
  4. tumor suppressor gene
18.

Which molecule is a Cdk inhibitor or is controlled by p53?

  1. anti-kinase
  2. cyclin
  3. p21
  4. Rb
19.

Which eukaryotic cell cycle events are missing in binary fission?

  1. cell growth
  2. DNA duplication
  3. karyokinesis
  4. cytokinesis
20.

Which of the following statements about binary fission is false?

  1. In both prokaryotic and eukaryotic cells, the outcome of cell reproduction is a pair of daughter cells, which are genetically identical to the parent cell.
  2. Karyokinesis is unnecessary in prokaryotes because there is no nucleus.
  3. Replication of the prokaryotic chromosome begins at the origin of replication and continues in both directions at once.
  4. The mitotic spindle draws the duplicated chromosomes to the opposite ends of the cell followed by formation of a septum and two daughter cells.
21.

The formation of what structure, which will eventually form the new cell walls of the daughter cells, is directed by FtsZ?

  1. contractile ring
  2. cell plate
  3. cytoskeleton
  4. septum
Sours: https://openstax.org/books/biology-ap-courses/pages/10-review-questions
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