Topic 16
Inheritance and variation
H
,Inheritance :
$
DNA -
Passing genetic material from one generation to another gene
-
=
Mother and the other
-
from the father
Homologous pair of
chromosomes
Two chromosomes ( one pair)
identical.,.having same length ,
shape and genes Chromosome
Yet one from mother and the
aeries
other form father Length of DNA that has
23pairs of Mother father specific sequence of bases
[ chromosomes
) - -
and code for a specific
protein to give specific char .
Elector green Blue acteristic
Alleles for eye colour: ctiromosomegm
. .
- -
Green, blue , brown Shaped lobbed lobbed
ear
The thread of DNA , made up
= =
Allele for hair colour : straight of genes
typed curly
Yellow, brown , black , gold
.
.
hair
we have 23pairs
same genes but I
different 1-
may be Samet
of genes 235am 23 Fom '
Forms .
== =
Mother
, Mother Father
1. Inheritance
2. Chromosomes
3. Gene → heterozygous
4. Allele : different forms of same gene Blue Blue
5. Homozygous : two identical alleles for a particular gene
→
homozygous
6. Heterozygous : two different alleles for a particular gene → homo
7. Dominant allele: allele that is expressed whenever. It is
lobed lobed lobed
present in both homozygous and heterozygous
→
8. Recessive allele: allele that is expressed only in absence → heterozygous .
of dominant allele lubed
→
(capital letter)
-
no lobe nowbe
So only expressed in homozygous recessive ( in presence of → non lubed
-
.
two recessive alleles) (small letter) .
9. Genotype : genetic make up
10. Phenotype : physical appearance of an organism due to
genes and environmental factors BB Bbobb
,
Brown , Blue eye colour .
11. Diploid ; cells containing 2 sets of chromosomes / a full
=
set of chromosomes 2h o
-
2×23
example human cells →
23 pairs .
12, haploid : cells containing half set of chromosome / half
the number of chromosomes N example egg cell 23
spermcell 23
, .flower
9
Colour of petals
Red / white
Red is dominant feature
White is recessive feature
Red ..............R
White .............r rr RRIRR
.
RR.........phenotype red
Rr...........phenotype red
Dominant
.EE#nexnoPem%ed
rr............phenotype white →
heterozygous .
White is a recessive feature controlled by recessive allele
As it needs two recessive alleles to be inherited one from each parent to becime expresssed
Inheritance and variation
H
,Inheritance :
$
DNA -
Passing genetic material from one generation to another gene
-
=
Mother and the other
-
from the father
Homologous pair of
chromosomes
Two chromosomes ( one pair)
identical.,.having same length ,
shape and genes Chromosome
Yet one from mother and the
aeries
other form father Length of DNA that has
23pairs of Mother father specific sequence of bases
[ chromosomes
) - -
and code for a specific
protein to give specific char .
Elector green Blue acteristic
Alleles for eye colour: ctiromosomegm
. .
- -
Green, blue , brown Shaped lobbed lobbed
ear
The thread of DNA , made up
= =
Allele for hair colour : straight of genes
typed curly
Yellow, brown , black , gold
.
.
hair
we have 23pairs
same genes but I
different 1-
may be Samet
of genes 235am 23 Fom '
Forms .
== =
Mother
, Mother Father
1. Inheritance
2. Chromosomes
3. Gene → heterozygous
4. Allele : different forms of same gene Blue Blue
5. Homozygous : two identical alleles for a particular gene
→
homozygous
6. Heterozygous : two different alleles for a particular gene → homo
7. Dominant allele: allele that is expressed whenever. It is
lobed lobed lobed
present in both homozygous and heterozygous
→
8. Recessive allele: allele that is expressed only in absence → heterozygous .
of dominant allele lubed
→
(capital letter)
-
no lobe nowbe
So only expressed in homozygous recessive ( in presence of → non lubed
-
.
two recessive alleles) (small letter) .
9. Genotype : genetic make up
10. Phenotype : physical appearance of an organism due to
genes and environmental factors BB Bbobb
,
Brown , Blue eye colour .
11. Diploid ; cells containing 2 sets of chromosomes / a full
=
set of chromosomes 2h o
-
2×23
example human cells →
23 pairs .
12, haploid : cells containing half set of chromosome / half
the number of chromosomes N example egg cell 23
spermcell 23
, .flower
9
Colour of petals
Red / white
Red is dominant feature
White is recessive feature
Red ..............R
White .............r rr RRIRR
.
RR.........phenotype red
Rr...........phenotype red
Dominant
.EE#nexnoPem%ed
rr............phenotype white →
heterozygous .
White is a recessive feature controlled by recessive allele
As it needs two recessive alleles to be inherited one from each parent to becime expresssed
