Good News: Now View/Read Notes & Lectures anytime, anywhere at your Mobile.

Download 8th Class General Science Notes (Unit # 2) for Islamabad Model Schools & Colleges

Download 8th Class General Science Notes (Unit # 2) for Islamabad Model Schools & Colleges

Very Easy, Updated & Comprehensive Notes for all types of students i.e. Average / Extra Ordinary

Note: 
  • Please subscribe our SMS Alerts Service, Email Updates and Like our Facebook Page from right sidebar to get latest updates regarding our notes & other material/posts.
  • You can also install our Mobile App to view/read our notes anytime, anywhere on mobile.
  • Please inform us regarding any correction/mistake (if found) by Contacting Us.
  • Please SHARE this page from below, if you like these Notes to support us.

Download 8th Class General Science Notes (Unit # 2) for Islamabad Model Schools & Colleges

SHORT QUESTIONS
Define the followings:
Mitosis:
Mitosis is the division of a nucleus into two identical daughter nuclei in which the number of chromosomes remains same.
Meiosis:
Meiosis is the division that results in four daughter cells each with half the number of chromosomes of the parent cell.
Chromosomes:
Chromosomes are thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Heredity:
The passing of characteristics from one generation to next is called heredity.
Gene:
Gene is a unit of heredity which is transferred from a parent to offspring. It determine characteristic of the offspring.
Genetics:
The passing of characteristics from one generation to next is called heredity. The science of heredity is called genetics.

Where does mitosis occur?
Mitosis takes place in the somatic cells (body cells) of an organism.

State where does meiosis take place in human males and in females?
Meiosis occurs in the special cells of sex organs. In males meiosis produces sperms and in females meiosis produce ovaries.

Where does meiosis occur in plants?
Meiosis occurs in the special cells of sex organs. In plants, anther produce pollens and ovaries produce egg cells.

What are the steps of mitosis?
i)      Prophase    ii)     Metaphase         iii)    Anaphase
iv)     Telophase  v)     Cytokinesis

What are the steps of meiosis?
Meiosis-I
i)            Prophase-I
ii)           Metaphase-I
iii)         Anaphase-I
iv)         Telophase-I
Meiosis-II
i)            Prophase-II
ii)           Metaphase-II
iii)         Anaphase-II
iv)         Telophase-II
The number of chromosomes in fruit fly is 8. What is the number of chromosomes in its sperm or egg?
There are 4 chromosomes in sperm and 4 in egg.

Draw and label a nucleotide?

Name the four nitrogenous bases of DNA.
The four nitrogenous bases present in DNA are:
i)            Adenine (A)
ii)           Guanine (G)
iii)         Cytosine (C)
iv)         Thymine (T)

What is a gene?
Gene is a unit of heredity which is transferred from a parent to offspring. It determine characteristic of the offspring


LONG / EXTENSIVE QUESTIONS

What is heredity? Explain.
  • The passing of characteristics from one generation to the next is called heredity.
  • A nucleus is present in all cells.
  • The nucleus contains thread-like structure called the chromosomes.
  • The chromosomes carry the genes that control all your characteristics.
  • Chromosomes occur in pairs.

What is the importance of (a) heredity (b) mitosis (c) meiosis?
a)   The process of heredity is responsible for passing the characteristics from one generation to next.
b)   All the cells of body divide through mitosis. So it is important for growth as well as for asexual reproduction.
c)   Sexual Reproduction takes place through meiosis.


Describe the process of mitosis in an animal cell.
It consists of following stages:
Prophase:
  • Chromosomes shorten, flatten and become visible.
  • Chromosomes divides into a pair of identical chromatids joined to one another by the centromere.
  • The centriols take up the position of opposite sides of nucleus.
  • A spindle fiber begins to form.
  • The nuclear membrane breaks down.
Metaphase:
  • The chromosome line up on the middle of the cell.
  • Each chromosome is connected to a different spindle fibre coming from opposite poles at its centromere.
Anaphase:
  • The chromatids separate into individual chromosome due to separation of centromere which is separated due to the pull created by the spindle fibres coming from opposite poles and move to the opposite end of the cell.
Telophase:
  • The chromosomes gather at opposite end of the cell.
  • A nuclear membrane forms around each group of chromosomes.
Cytokinesis:
  • The division of the cell is called cytokinesis.
  • The cytoplasm pinches in half.
  • Each daughter cell has an identical set of chromosomes.

Describe the process of meiosis in an animal cell.
Meiosis has two clear divisions Meiosis I and Meiosis II.
A)     Meiosis I
This is made up of 4 stages
i)       Prophase I
  • Chromosomes shorten, flatten and become visible.
  • Chromosomes divides into a pair of identical chromatids joined to one another by the centromere.
  • Spindle fiber begins to form.
ii)      Metaphase I
  • The homologous chromosome line up on the middle of the cell.
  • Chromosomes are attached to spindle fibers by centromere.
iii)     Anaphase I
  • The spindle fibers shorten and the chromosomes separate going to opposite poles.
iv)     Telophase I
  • The chromosomes gather at opposite end of the cell.
  • Each daughter cell has a half set of chromosomes the parent cell.



B)     Meiosis II
This is very similar to Mitosis.
i)       Prophase II
  • Two cells were formed at the end of Meiosis-I.
  • Nuclear envelop break down, spindle fibers forms.
ii)      Metaphase II
  • The chromosomes align themselves on equator attached at spindle fibers.
iii)     Anaphase II
  • Spindle Fibers shorten separating the chromatid. This pulls the chromatids in opposite poles.
iv)     Telophase II
  • The nuclear envelop forms around each cell of chromosomes.
  • As a result of cytokinesis, the cells will split to form 4 daughter cells.

What are the difference between mitosis and meiosis?
Mitosis
Meiosis
It takes place in body cells.
It takes place in sex cells.
Two daughter cells are formed
Four daughter cells are formed.
Daughter cells are identical to parent cell.
Daughter cells are not identical to parent cell.
The number of chromosomes remains same.
The number of chromosomes becomes half.
The function includes general growth.
The function includes producing organisms having different characteristics.

Describe the structure of DNA.
·        The sugar deoxyribose and phosphate group join up and form the backbone of the DNA strand.
·        The bases are attached to the sugar deoxyribose molecules.
·        DNA strand is made of two strands of nucleotides. It looks like a ladder.
·        The upright part of the ladder is made up of deoxyribose and phosphate group.
·        The “rungs” in the ladder consist of four bases.

·        And then the whole molecules twisted into a double helix 4 a bit like a spiral staircase.

COMMENTS

Name

10th Class Notes,88,10th Class Old Papers,2,1st Year Notes,11,5th Class Notes,6,6th Class Notes,61,6th Class Old Papers,2,7th Class Notes,55,7th Class Old Papers,2,8th Class Notes,66,8th Class Old Papers,2,9th Class Notes,88,9th Class Old Papers,2,Articles,1,Download Free E-Books on IT,1,Guess Papers,11,Home Tutors,4,Home Tutors in Islamabad & Rawalpindi,15,Home Tutors in Jhang,1,Home Tutors in Karachi,2,Home Tutors in Lahore,4,Home Tutors in Multan,1,Home Tutors in Rahim Yar Khan,1,Home Tutors in Wah Cantt & Taxila,3,Important Questions,11,Information Technology,1,Miscellaneous,10,News & Events,4,Notes & Handouts,377,Old Papers,11,Solved AIOU Assignments,1,Video Lectures,1,
ltr
item
Download Class Notes: Download 8th Class General Science Notes (Unit # 2) for Islamabad Model Schools & Colleges
Download 8th Class General Science Notes (Unit # 2) for Islamabad Model Schools & Colleges
Download 8th Class General Science Notes (Unit # 2) for Islamabad Model Schools & Colleges
https://3.bp.blogspot.com/-AD_k26oqv6M/WKmkI3ZgW2I/AAAAAAAADfQ/T7RZ-z-t5N8s8Qc12AlSOm0wc0W69Vr9wCLcB/s1600/8th_class_general_science_notes_fbise_islamabad_model_schools_colleges_federal_directorate_of_education_by_shahzad_iftikhar.jpg
https://3.bp.blogspot.com/-AD_k26oqv6M/WKmkI3ZgW2I/AAAAAAAADfQ/T7RZ-z-t5N8s8Qc12AlSOm0wc0W69Vr9wCLcB/s72-c/8th_class_general_science_notes_fbise_islamabad_model_schools_colleges_federal_directorate_of_education_by_shahzad_iftikhar.jpg
Download Class Notes
http://www.downloadclassnotes.com/2016/10/unit-2-download-8th-class-viii-general-science-notes-for-islamabad-model-schools-colleges.html
http://www.downloadclassnotes.com/
http://www.downloadclassnotes.com/
http://www.downloadclassnotes.com/2016/10/unit-2-download-8th-class-viii-general-science-notes-for-islamabad-model-schools-colleges.html
true
6576910405746451012
UTF-8
Loaded All Posts Not found any posts VIEW ALL Readmore Reply Cancel reply Delete By Home PAGES POSTS View All RECOMMENDED FOR YOU LABEL ARCHIVE SEARCH ALL POSTS Not found any post match with your request Back Home Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sun Mon Tue Wed Thu Fri Sat January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec just now 1 minute ago $$1$$ minutes ago 1 hour ago $$1$$ hours ago Yesterday $$1$$ days ago $$1$$ weeks ago more than 5 weeks ago Followers Follow THIS CONTENT IS PREMIUM Please share to unlock Copy All Code Select All Code All codes were copied to your clipboard Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy