Summary INTRODUCTION TO BIOLOGY USING CAMPBELL BIOLOGY TEXT BOOK
9 views 0 purchase
Course
Introductory Life Science
Institution
University Of The Witwatersrand (wits)
"STUDYING THE CAMPELL BIOLOGY TEXT BOOK CAN BE QUITE EXHAUSTING!". THATS A LIE IF YOU GO THROUGH THESE SUMMARIES OF SOME OF THE CHAPTERS.
GET A DETAILED YET SUMMARISED VERSION OF SOME OF THE CHAPTERS IN THE BIOLOGY CAMPBELL TEXTBOOK
Choice of Experimental Organism
• Pea Plants (Pisum sativum): Mendel chose pea plants because they have
distinct, heritable traits, can be easily manipulated in breeding
experiments, and have a relatively short generation time.
Mendel's Techniques
• Controlled Cross-Pollination: Mendel manually cross-pollinated plants to
control parentage and track traits through generations.
• True-Breeding Lines: Mendel used plants that, when self-pollinated,
consistently produced offspring with the same traits.
Key Principles from Mendel's Work
Monohybrid Crosses
• Single Trait Crosses: Mendel studied one trait at a time (e.g., flower color)
by crossing true-breeding plants with different traits.
• F1 and F2 Generations: Crossed plants with contrasting traits (e.g., purple
and white flowers), observed the F1 generation (all purple), and then self-
pollinated F1 to produce the F2 generation, showing a 3:1 ratio of traits.
Law of Segregation
• Alleles and Gametes: Each individual has two alleles for each gene, which
segregate during the formation of gametes. Thus, each gamete carries only
one allele.
• Dominant and Recessive Alleles: Dominant alleles mask the expression of
recessive alleles in heterozygotes.
, Dihybrid Crosses and Independent Assortment
Two-Trait Crosses
• Studying Two Traits Simultaneously: Mendel crossed plants differing in two
traits (e.g., seed shape and seed color) to see if traits are inherited
independently.
• 9:3:3:1 Ratio: Observed in the F2 generation, indicating that alleles of
different genes assort independently during gamete formation.
Law of Independent Assortment
• Independent Assortment: Alleles of different genes segregate
independently of each other during gamete formation, leading to genetic
variation.
Extensions of Mendelian Genetics
Incomplete Dominance
• Intermediate Phenotype: Heterozygotes show a phenotype that is
intermediate between the two homozygous phenotypes (e.g., red and
white snapdragon flowers producing pink offspring).
Codominance
• Both Alleles Expressed: In heterozygotes, both alleles are fully expressed
(e.g., AB blood type where both A and B alleles are expressed).
Multiple Alleles
• More than Two Alleles: For some genes, more than two alleles exist within
a population (e.g., ABO blood group system with three alleles: I^A, I^B, i).
Pleiotropy
• One Gene, Multiple Effects: A single gene influences multiple phenotypic
traits (e.g., sickle cell disease affecting red blood cells, resistance to malaria,
etc.).
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 zinhlegazide. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.50. You're not tied to anything after your purchase.
