Cambridge International AS and A Level Biology Coursebook with CD-ROM
Biology cie 9700 A level notes on topic 16( 5th topic from A level section)
summary made out of notes from both CIE textbook, classnotes and past papers. covers all the syllabus checklist for 2018.
Achieved 91% on my biology A level this june. Prepared for the exam using these notes and past pape...
Genetic information is transmitted from generation to generation to maintain the continuity of life. In
sexual reproduction, meiosis introduces genetic variation so that offspring resemble their parents but
are not identical to them. Genetic crosses reveal how some features are inherited. The phenotype
of organisms is determined partly by the genes they have inherited and partly by the effect of the
environment. Genes determine how organisms develop and gene control in bacteria gives us a glimpse of
this process in action.
Passage of information from parent to offspring
Diploid organisms contain pairs of homologous chromosomes. The behaviour of maternal and paternal
chromosomes during meiosis generates much variation amongst individuals of the next generation.
Homologous chromosomes: are a pair of chromosomes in a diploid cell that have the
same structure as each other, with the same genes (but not necessarily he same alleles of
those genes) at the same loci, and that pair together to form a bivalent during the first
division of meiosis.
Diploid (2n): a diploid cell is one that possess 2 complete sets of chromosomes.
Haploid (n): a haploid cell is one that possesses one complete set of chromosomes.
N= the number of chromosomes in one set of chromosomes
In humans normal body cells are diploid, with 46 chromosomes, and gametes are
haploid with 23 chromosomes.
Meiosis is a special type of cell division concerned with producing sex cells (gametes)
fro sexual reproduction.
Fro the life cycle to contain sexual reproduction. Before fertilisation chromosome is
haled results in gametes containing only one set of chromosomes instead of 2.
If not number of chromosomes would double each generation. Meiosis = nuclear
division that halves the chromosomes. ( reduction division)
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 Cnts. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.91. You're not tied to anything after your purchase.
