Summary
Summary Cell Division: Meiosis
- Course
- Institution
- Book
Matric CAPS Cell Division.
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
More summaries for
-
Reproduction in Vertebrates Notes
-
DNA Summary Grade 12
-
Endocrine System Summary Grade 12
Seller
Follow
charlottiiieeeg
Reviews received
Available practice questions
Cell Division: Meiosis
Flashcards
33 Flashcards
$1.70
0 sales
Flashcards
33 Flashcards
$1.70
0 sales
Some examples from this set of practice questions
1.
Describe the structure of a chromosome
Answer: - chromatin network unwinds to form chromosomes - long strands of DNA wrapped by outer protein covering -DNA is made up of nucleotides
2.
What is a gene
Answer: a short strand of DNA
3.
What is non-coding DNA
Answer: non-functional DNA
4.
How many chromosomes does a somatic cell have
Answer: 46, it is diploid
5.
How many chromosomes does a sex cell have
Answer: 23, it is haploid
6.
How many pairs of gonosomes are there
Answer: 1
7.
How many pairs of autosomes are there
Answer: 22
8.
What is the genotype for a female?
Answer: XX
9.
What is the genotype for a male?
Answer: XY
10.
When does meiosis occur
Answer: During gametogenisis, the formation of gametes (sex cells)
Content preview
CHAPTER TWOCELL DIVISION: MEIOSIS
STRUCTURE OF CHROMOSOMES
1. Chromatin Network unwinds to form chromosomes
2. Chromosomes are long strands of DNA wrapped by outer protein covering
3. DNA is made up of nucleotides
CHROMOSOMES IN SOMATIC AND SEX CELLS
● Somatic cells: made of 46 chromosomes. They are diploid.
● Sex cells: made of 23 chromosomes. They are haploid.
● 22 pairs of autosomes, 1 pair of gonosomes (X and/or Y chromosomes)
● Female has XX gonosomes
● Male has XY gonosomes
● One gonosome is maternal whilst the other is paternal but they are
identical in terms of type/order of gene(s).
Karyotype:a picture of a person's
chromosomes. Ordered from 1 to 22 in
descending order of size. The X and Y
chromosomes determine gender and are
shown in the 23rd slot on the
karyotype.
Sometimes, due to incorrect splitting
of chromosomes, a karyotype may show
that an extra chromosome may be
present or one may not be present.
Sometimes, no chromosomes of a
specific number may be seen.
, MEIOSIS
● Dividing one cell into four cells
● Occurs during gametogenesis
Gametogenesis: process which take place wherein gametes (sex cells) are formed
CHROMOSOME NUMBER
● Human chromosome number is 46
● The halving effect, which brings the chromosome number per sex cell down
to 23, is very important (to prevent chromosome number from doubling
eternally. ie 23,46,92...)
● The doubling effect allows the chromosome number to increase back up to
46. It happens when two haploid cells (Sperm and ovum) fuze to form a
diploid cell.
● Having one too many or one too little chromosomes may lead to
deformities such as down syndrome.
MEIOSIS BEFORE FERTILISATION (DURING GAMETE FORMATION)
● ie Humans
● Takes place when the gametes are formed
● It halves the chromosome number with the halving effect
● Fusion of two haploid cells creates a diploid cell (zygote)
MEIOSIS AFTER FERTILISATION
● ie Algae
● Haploid spores give rise to haploid gametes
● Fertilization results in a diploid zygote
● Zygote undergoes meiosis to produce haploid spores
MEIOSIS IN MOSS/FERNS
● Alternates between haploid gametophytes and diploid sporophytes
● The halving effect allows for this alternation
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller charlottiiieeeg. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $2.84. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
64438 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now