Learning
Question
What is
inheritance?
Success Criteria
Topics to research:
(a) Explain what is meant by “DNA” (structure, location,
function, how it was discovered).
(b) Explain what is meant by “chromosomes” (location,
structure, function, number, etc.)
(c) Explain what is meant by “genes” and “alleles” and how
they affect our appearance/characteristics. How do different
alleles cause increased variation.
(d) Describe the ways that we are both similar and different
to our parents due to our genes (refer to phenotype).
(e) Explain what is meant by “inheritance” and how
variations can be inherited from our parents (refer to
gametes, genes and chromosomes).
What is DNA?
DNA
• The full name for DNA is deoxyribonucleic
acid
• DNA contains genetic information for an
individual that determines the characteristic
of a living thing
• DNA is made of 2 strands that is wound into a
double helix
What are genes?
Genes
• A gene is a short section of DNA
• Genes carry the coding for a particular protein
• Different genes control the development of
different characteristics of an organism
• Example:
– The human insulin gene codes for the
production of the hormone insulin
Many genes are needed to carry all the genetic
information for a whole organism
What are chromosomes?
Chromosomes
• Chromosomes are found in the nucleus
of the cell
• Chromosomes contain genes and are
made of DNA
http://www.youtube.com/watc
h?v=V9BZ3zx8b8I
What is DNA?
Did you know!!
The number of genes and chromosomes
varies from species to species. For
example, cells in human beings have 46
chromosomes that carry about 30,000
genes in each cell; and cells in fruit flies
have 8 chromosomes that carry about
13,600 genes
What is the human
chromosome compliment?
Human Chromosome Compliment
• The human chromosome compliment is
46
• 23 pairs
– (2 sets – one set from
each parent)
Not all organisms have 46
chromosomes!
Not all organisms have 46
chromosomes!
Not all organisms have 46
chromosomes!
Not all organisms have 46
chromosomes!
Not all organisms have 46
chromosomes!
http://www.neok12.com/video/G
enetics/zX57774078797d75646
Do all cells have 46 chromosomes?
Body Cells
• Body cells contain 2 sets of
chromosomes (23 pairs = 46)
• 1 set is inherited from your mother
• 1 set is inherited from your father
= 2 SETS
Do all cells have 46 chromosomes?
Sex Cells (gametes)
• Sex cells (also called gametes) contain 1
set of chromosomes (= 23)
• Sperm & Egg cells contain 23
chromosomes (1 set)
Red Blood Cells
• Red blood cells do not contain a nucleus (so do
not contain chromosomes) therefore do not
contain genetic information
Do all cells have 46 chromosomes?
Inheritance
• Inheritance is the passing on of
genes from parents to offspring
• Fertilisation is when the nuclei of
the male and female gamete fuse
together to form a zygote
• The zygote has 23 pairs of
chromosomes ( 2 sets = 46)
1.
2.
3.
4.
5.
6.
What does DNA stand for?
What are long sequences of DNA known as?
Give an example of what a sequence of DNA could code for.
What are chromosomes?
Where are chromosomes found?
How many chromosomes are found in:
1.
2.
7.
How many sets of chromosomes are found in
1.
2.
8.
Body Cells
Sex Cells (gametes)
Body Cells
Sex Cells (gametes)
What is inheritance?