B1H REVISION NOTES

SINGLE SCIENCE, OCR BOARD - HIGHER TIER, BIOLOGY - B1H

HideShow resource information
Preview of B1H REVISION NOTES

First 46 words of the document:

How characteristics are inherited
We inherit dominant or recessive genes from our parents
If there is a dominant gene in a pair that characteristic is
inherited
Recessive characteristics only show if there are two
recessive genes in a pair

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Example of Dominant and Recessive genes
Brown hair allele is dominant ( B )
Blonde hair allele is recessive ( b )
If the male has brown hair and is homozygous ( BB ) and the
female has blond hair and is homozygous ( bb ) what colour hair
will their children have ?
B B
b Bb Bb
b Bb Bb
All offspring will have brown hair and be heterozygous…read more

Page 3

Preview of page 3

Here's a taster:

Inherited disorders
Most inherited disorders are caused by faulty genes, most
of which are recessive…read more

Page 4

Preview of page 4

Here's a taster:

Example of Inherited disorders
Allele for no cystic fibrosis is dominant ( C )
allele for cystic fibrosis is recessive ( c )
A carries does not have cystic fibrosis because they are
heterozygous for the diseases ( Cc ), will their children have
cystic fibroses ?
C c
C CC Cc
c Cc cc
C c
C CC Cc
C CC Cc
C c
c Cc cc
c Cc cc…read more

Page 5

Preview of page 5

Here's a taster:

Mutations
Mutations are caused by the miss ­ copying of the gene
sequence which DNA replicates, divides and copies
This can be caused be several factors :
Spontaneously at random
Diseases e.g.…read more

Page 6

Preview of page 6

Here's a taster:

Genetic Word and definitions
Chromosome
A chromosome is a long string of DNA containing genes
DNA
DNA contains genes ; made from 4 basis G, C, A and T
Gene
A gene is a section of DNA that makes a particular protein ;
determines character
Allele
An allele is a different version / form the same gene
Gamete
A gamete is a sex cell
Homozygous
Two genes that are identical
Heterozygous
Two genes that are different
Dominant
A dominant gene hides the effects of a…read more

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »