Biology 10th ICSE: Genetics Flashcards
What is Genetics?
The study of heredity
What is heredity?
transmission of genetically based characteristics from parents to offspring.
How many chromosomes does a human have?
46 Chromosomes present in 23 pairs
What are chromosomes 1-22 called?
Autosomes. They are identical
What is the 23rd pair of chromosome called?
Sex Chromosomes or Allosome
They are different from the other chromosomes
They are either an X or Y chromosome.
What kind of chromosomes can be contained by the Egg?
It only contains the X chromosome
What kind of chromosomes can be contained by the Sperm?
It can contain either X or Y chromosome and thus determines the gender of the offspring
State the combination of X or Y chromosomes that produces a female.
XX chromosomes produce a female offspring
State the combination of X or Y chromosomes that produces a male.
XY chromosomes produce a male offspring
Who coined the term ‘Gene’
Wilhelm Johanssen in 1909
not v important but im still gonna put it in anyway ¯_( ͡° ͜ʖ ͡°)_/¯
What is an ‘Allele’?
Every gene has 2 alternative forms for a characteristic (either on or off
ie. Can tongue roll, OR Cannot tongue roll).
These forms are called Alleles
What is a Genotype?
The set of genes present in the cells of an organism
What is a Phenotype?
the observable characteristics which are genetically controlled
What is a dominant allele?
It expresses itself regardless of the presence of another Allele
What is a recessive allele?
Its expression is supressed in the presence of a dominant allele
What represents a homozygous dominant genotype?
RR
rr if recessive
What represents a heterozygous genotype?
Rr
rR is not a thing 🙄
What is Mendel’s law of dominance?
Between a pair of contrasting characteristics, only 1, the dominant one expresses itself
What is Mendel’s law of Segregation?
The 2 members of a pair of factors separate during the formation of gametes and do not blend
(wtvr that means ig)
What is mutation?
A sudden change in one or more genes, or in the number or structure of chromosomes
Name and briefly describe 2 mutations.
Sickle Cell Anaemia
- Change in DNA results in Sickle shaped RBC’s
Radioactive Radiations
- number of deformities in both plants and animals
