• Skip to main content
  • Skip to secondary menu
  • Skip to primary sidebar
  • Skip to footer

CBSE Tuts

CBSE Maths notes, CBSE physics notes, CBSE chemistry notes

  • NCERT Solutions
    • NCERT Solutions for Class 12 English Flamingo and Vistas
    • NCERT Solutions for Class 11 English
    • NCERT Solutions for Class 11 Hindi
    • NCERT Solutions for Class 12 Hindi
    • NCERT Books Free Download
  • TS Grewal
    • TS Grewal Class 12 Accountancy Solutions
    • TS Grewal Class 11 Accountancy Solutions
  • CBSE Sample Papers
  • NCERT Exemplar Problems
  • English Grammar
    • Wordfeud Cheat
  • MCQ Questions

The Structure of a Cell and Micro-organisms – Maharashtra Board Class 8 Solutions for General Science

The Structure of a Cell and Micro-organisms – Maharashtra Board Class 8 Solutions for General Science (English Medium)

MathematicsGeneral ScienceMaharashtra Board Solutions

Solution 1.a:

Characteristics of the cell membrane:

  1. It is the outermost covering of the cell.
  2. It is very thin and flexible.
  3. It protects the inner parts of the cell.
  4. It regulates the flow of substances which enter and leave the cell.
  5. It maintains the shape of the cell.

Solution 1.b:

Functions of the nucleus:

  1. It controls and regulates all the functions of the cell.
  2. It takes active part in the process of cell division.
  3. The genes located on the chromosomes in the nucleus help to transmit the inherited characteristics from the parental generation to the next generation.

Solution 1.c:

Functions of vacuoles:

  1. They store the products of excretion.
  2. They also store secretions of the cell temporarily.

Solution 2.a:
3. plastids
Ribosomes, mitochondria and nucleus are present in both plant and animal cells.

Solution 2.b:
3. nucleus
Chromosomes contain DNA which carries genetic information.

Solution 2.c:
1. plant
The plant cell contains chloroplasts which assist in photosynthesis.

Solution 3.a:

Mitochondria:

  1. Mitochondria are primarily tubular in shape.
  2. They are double-walled membranous structures with folds on the inner membrane.
  3. They produce energy from the food material present in the cell.
  4. This energy is supplied whenever required by the cell.
  5. Mitochondria are therefore called the powerhouses of the cell.

Solution 3.b:

Antibiotics:

  1. Antibiotics are substances produced from microorganisms which kill other microorganisms.
  2. In 1929, Alexander Fleming discovered the antibiotic penicillin during the growth of the fungus Penicillium.
  3. Only certain bacteria are able to produce certain antibiotics.
  4. An antibiotic can kill only specific microorganisms.
  5. For example, the antibiotic penicillin kills diphtheria and pneumonia germs, chloromycetin kills typhoid germs and streptomycin kills tuberculosis germs.

Solution 3.c:

Harmful bacteria:

Bacteria which produce harmful effects on human beings are called harmful bacteria.

  1. Staphylococcus bacteria produce a poisonous substance called enterotoxin as it grows on foodstuffs. After entering the body, this substance causes vomiting and diarrhoea.
  2. Clostridium bacteria produce toxic substances in expired canned food. Such foodstuffs cause vomiting and diarrhoea if consumed.
  3. Diseases such as typhoid, tuberculosis, diphtheria and pneumonia are also caused by bacterial infection.

Solution 3.d:

Useful bacteria:

Bacteria which are beneficial to human beings are called useful bacteria.

  1. The Rhizobium bacteria found in the root nodules of leguminous plants are used as nitrogen-fixing agents. They convert the nitrogen in the air into nitrogenous compounds. These nitrogenous compounds enter the soil and make it fertile.
  2. The bacterium Azotobacter lives independently and fixes atmospheric nitrogen into nitrogenous compounds.
  3. Soil contains several bacteria which decompose the dead and decaying matter of several plants and animals and produce humus. This increases the fertility of the soil.

Solution 4:

  • The name ‘cell’ was first used by the scientist Robert Hooke.
  • The cell wall of the plant cell consists of the substance cellulose.
  • The cell wall is found only in the plant cell.
  • Mitochondria is the powerhouse of the cell.
  • The cell membrane is the outer covering of the cell.

Solution 5.a:

Differences between plant cells and animal cells:

S.No. Plant cells Animal cells
1. The cell wall is the outermost covering of the plant cell. The cell membrane is the outermost covering of the animal cell.
2. Cell wall is present. Cell wall is absent.
3. Vacuoles are larger and more in number. Vacuoles are smaller and fewer.
4. Chlorophyll is present. Chlorophyll is absent.

Solution 5.b:

Differences between cell membrane and cytoplasm:

S.No.  Cell membrane Cytoplasm
1. The cell membrane is the outer covering of the cell. The cytoplasm is a substance inside the cell.
2. It protects the inner parts of the cell. It has cell organelles embedded in it.
3. It is a thin, flexible membrane. It is a semi-fluid substance.
4. It is made of lipids and proteins. It is made of organic and inorganic substances.
5. It regulates the flow of substances in and out of the cell. The cell organelles embedded in the cytoplasm carry out various life processes of the cell.

 

 

Primary Sidebar

NCERT Exemplar problems With Solutions CBSE Previous Year Questions with Solutoins CBSE Sample Papers
  • The Summer Of The Beautiful White Horse Answers
  • Job Application Letter class 12 Samples
  • Science Lab Manual Class 9
  • Letter to The Editor Class 12 Samples
  • Unseen Passage For Class 6 Answers
  • NCERT Solutions for Class 12 Hindi Core
  • Invitation and Replies Class 12 Examples
  • Advertisement Writing Class 11 Examples
  • Lab Manual Class 10 Science

Recent Posts

  • Understanding Diversity Question Answer Class 6 Social Science Civics Chapter 1 NCERT Solutions
  • Our Changing Earth Question Answer Class 7 Social Science Geography Chapter 3 NCERT Solutions
  • Inside Our Earth Question Answer Class 7 Social Science Geography Chapter 2 NCERT Solutions
  • Rulers and Buildings Question Answer Class 7 Social Science History Chapter 5 NCERT Solutions
  • On Equality Question Answer Class 7 Social Science Civics Chapter 1 NCERT Solutions
  • Role of the Government in Health Question Answer Class 7 Social Science Civics Chapter 2 NCERT Solutions
  • Vital Villages, Thriving Towns Question Answer Class 6 Social Science History Chapter 9 NCERT Solutions
  • New Empires and Kingdoms Question Answer Class 6 Social Science History Chapter 11 NCERT Solutions
  • The Delhi Sultans Question Answer Class 7 Social Science History Chapter 3 NCERT Solutions
  • The Mughal Empire Question Answer Class 7 Social Science History Chapter 4 NCERT Solutions
  • India: Climate Vegetation and Wildlife Question Answer Class 6 Social Science Geography Chapter 8 NCERT Solutions
  • Traders, Kings and Pilgrims Question Answer Class 6 Social Science History Chapter 10 NCERT Solutions
  • Environment Question Answer Class 7 Social Science Geography Chapter 1 NCERT Solutions
  • Understanding Advertising Question Answer Class 7 Social Science Civics Chapter 7 NCERT Solutions
  • The Making of Regional Cultures Question Answer Class 7 Social Science History Chapter 9 NCERT Solutions

Footer

Maths NCERT Solutions

NCERT Solutions for Class 12 Maths
NCERT Solutions for Class 11 Maths
NCERT Solutions for Class 10 Maths
NCERT Solutions for Class 9 Maths
NCERT Solutions for Class 8 Maths
NCERT Solutions for Class 7 Maths
NCERT Solutions for Class 6 Maths

SCIENCE NCERT SOLUTIONS

NCERT Solutions for Class 12 Physics
NCERT Solutions for Class 12 Chemistry
NCERT Solutions for Class 11 Physics
NCERT Solutions for Class 11 Chemistry
NCERT Solutions for Class 10 Science
NCERT Solutions for Class 9 Science
NCERT Solutions for Class 7 Science
MCQ Questions NCERT Solutions
CBSE Sample Papers
NCERT Exemplar Solutions LCM and GCF Calculator
TS Grewal Accountancy Class 12 Solutions
TS Grewal Accountancy Class 11 Solutions