Download Revision of B5 - Blackpool Aspire Academy

Growth and Development (B5)
B5.1
How does an organism produce new cells?
DNA has a double helix
structure
The cell cycle
•
Cell cycle: the main processes
1. Cell growth during which
– The number of organelles increase
– The chromosomes are copied when the
two strands of each DNA molecule
separate and new strands form alongside
them
2. Mitosis during which
– Copies of the chromosomes separate
– The cell divides
1. Cell growth during which
– The number of organelles increase
– The chromosomes are copied when the two strands
of each DNA molecule separate and new strands form
alongside them
2. Mitosis during which
–Copies of the chromosomes separate
–The cell divides
• Cell Division by Mitosis: this
produces two new cells identical
to each other and to the parent
cell
How does an organism produce
new cells?
There are two types of cell division:
Mitosis
M_______
Meiosis
M_______
Meiosis
• A type of cell division that produces
gametes
• It is important in meiosis that the cells
produced only contain half the
chromosome number of the parent cell.
• A zygote contains a set of
chromosomes from each parent
Meiosis
Gametes
Zygote
Questions
• What happens in the normal cell cycle?
–Cell growth
–Mitosis
• What happens during cell growth?
–Number of organelles increase
–Chromosomes are copied by separating DNA
strands and forming new strands
• What happens during Mitosis?
–Copies of the chromosomes separate
–The cell divides
More questions
• In which organs do cells divide by Meiosis?
– Ovaries and Testes
• How many chromosomes are in the gamete
if the parent cell has 46?
– 23
• How many chromosomes does the zygote
have? Where are they from?
– 46
– A set from each gamete. (from each parent)
Growth and Development (B5)
B5.2
How do genes control growth and
development within the cell?
DNA - the genetic code
• The genetic code is in the cell nucleus
BUT proteins are produced in the cell
cytoplasm
Nucleus
Cytoplasm
Genes do not leave the nucleus but a copy of the gene is
produced to carry the genetic code to the cytoplasm
In the nucleus
Travels to the
cytoplasm
In the cytoplasm
Both strands of DNA are
made up of four different
bases.
The bases always pair up
in the same way
A -T
C-G
The Genetic Code
The order of the bases in a gene is the code
for building up amino acids in the correct order
to make a particular protein
Chromosome
made of DNA
In mRNA
U (not T)
mRNA copy
of gene
Protein made
of amino acids
Questions
Where are proteins made in cells?
In the cytoplasm
Where is the genetic code found? In the nucleus of every cell
How does the code get into the cytoplasm?
A copy of the gene carries the code (RNA)
How many different bases are in DNA?
Four different bases, always pairing the same way
How is the order of the amino acids in proteins determined?
The order of bases in a gene is the code
Growth and Development (B5)
B5.3
How do new organisms develop from a single
cell?
Early embryos
The zygote divides by mitosis to form an embryo
In a human
embryo, up to
the eight cell
stage, all the
cells are
identical and
could
produce any
sort of cell
required by
the organism
(embryonic
stem cells)
After this point the cells become
specialised and form different
types of tissue. Some of the
genes are switched off.
Specialised Cells
After this point the
cells become
specialised and form
different types of
tissue
 Although body
cells in an organism
contain the same
genes, many genes
in a particular cell
are not active
because it only
produces the
specific proteins it
needs
One cell type becomes many!
Gene switches
•Gene for
insulin is on in
the pancreas
but off in the
kidney
•Gene for ADH
is on in the
pituitary gland
but off in the
salivary gland
gametes
zygote
mitosis
Specialised
cell types in
tissues
Cloning
• In carefully controlled conditions of
mammalian cloning, it is possible to
reactivate inactive genes in the nucleus of
a body cell to form
cells of all tissue
types.
• Adult and embryonic stem cells have the
potential to produce cells needed to
replace damaged tissues.
Plants from from single cells
• New cells in plants specialise into cells
of roots, leaves or flowers.
Unlike animal cells some plant cells
remain unspecialised and can develop
into any type of plant cell.
These unspecialised
cells allow the
production of clones of
plants with desirable
features, from cuttings.
Plant meristems
• Plant meristems divide to
produce cells that result
in increased height,
length of roots and
girth of the plant.
If the hormonal conditions in their environment are
changed, unspecialised plant cells can develop into a range
of other tissues (eg xylem and phloem) or organs (eg
leaves, roots, flowers)
Cut stems from a plant can develop roots in the presence
of plant hormones (auxins) and grow into a complete plant
which is a clone of the parent
Phototropism
Phototropism is the plant’s response to light.
It increases the plant’s chance of survival
Light causes auxin to move to the opposite side of
the shoot tip. The cells on the side with more auxin
grow bigger.
REVISE
Check your knowledge
Growth and Development (B5)
B5.1
How does an organism produce
new cells?
double helix
DNA has a ____________
structure
The Cell Cycle
•
Cell cycle: the main processes
1. Cell growth during which
The number of organelles increase
- -______________________________
-___________________________
The chromosomes are copied when
the two strands of each DNA molecule
separate and new strands form alongside
them
2. Mitosis during which
– Copies
____________________________
of the chromosomes separate
– The
____________________________
cell divides
1.
–
–
Cell growth during which
The number of organelles increase
_______________________________
____________________________
The chromosomes are copied when the two
strands of each DNA molecule separate and new
strands form alongside them
2. Mitosis during which
____________________________
—Copies
of the chromosomes separate
— The cell divides
_______________________
• Cell Division by Mitosis: this
two new cells identical
produces ____
to each other and to the parent cell
How does an organism produce
new cells?
There are two types of cell division:
Mitosis
M_______
Meiosis
M_______
Meiosis
• A type of cell division that produces
gametes
• It is important in meiosis that the cells
produced only contain half the
chromosome number of the parent cell.
• A zygote contains a set of chromosomes
from each parent
Meiosis
Gametes
Zygote
Questions
• What happens in the normal cell cycle?
–Cell growth
–Mitosis
• What happens during cell growth?
–Number of organelles increase
–Chromosomes are copied by separating DNA
strands and forming new strands
• What happens during Mitosis?
–Copies of the chromosomes separate
–The cell divides
More questions
• In which organs do cells divide by Meiosis?
– Ovaries and Testes
• How many chromosomes are in the gamete
if the parent cell has 46?
– 23
• How many chromosomes does the zygote
have? Where are they from?
– 46
– A set from each gamete. (from each parent)
Growth and Development (B5)
B5.2
How do genes control growth and
development within the cell?
DNA - the genetic code
cell nucleus
• The genetic code is in the ________
BUT proteins are produced in the cell
cytoplasm
__________.
Nucleus
Cytoplasm
copy of the gene
Genes do not leave the nucleus but a _______________
is produced to carry the genetic code to the cytoplasm
In the nucleus
Travels to the
cytoplasm
In the cytoplasm
Both strands of DNA are
made up of ____
four different
bases.
The bases always pair up
_______________
in the same way
A-T
?
C -G
?
The Genetic Code
order of the bases
The _____________________
in a gene is
the code for building up amino acids in the
protein
correct order to make a particular ________.
Chromosome
DNA
made of ____
In mRNA
__
U (not T)
mRNA copy
____
__________
of gene
Protein made
of amino
__________.
acids
Questions
Where are proteins made in cells?
In the cytoplasm
Where is the genetic code found? In the nucleus of every cell
How does the code get into the cytoplasm?
A copy of the gene carries the code (RNA)
How many different bases are in DNA?
Four different bases, always pairing the same way
How is the order of the amino acids in proteins determined?
The order of bases in a gene is the code
Growth and Development (B5)
B5.3
How do new organisms develop from a single
cell?
Early embryos
The zygote divides by ________
mitosis to form an embryo
In a human
embryo, up to
the _____
eight
_____
cell stage,
all the cells
are identical
and could
produce any
sort of cell
required by
the organism
(embryonic
stem cells)
After this point the cells
become specialised
__________ and
form different types of
tissue
_________.
Specialised Cells
After this point the
cells become
specialised
________ and form
different types of
tissue
________.
 Although body
cells in an organism
contain the same
genes, many genes
in a particular cell
are _________
because
not activeit only
produces the
specific _________
itproteins
needs
One cell type becomes many!
Gene switches
•Gene for
insulin is on in
pancreas
the _________
but off in the
kidney
•Gene for ADH
is on in the
pituitary
gland
____________
but off in the
salivary gland
gametes
zygote
mitosis
Specialised
cell types in
tissues
Cloning
• In carefully controlled conditions of
mammalian cloning, it is possible to
reactivate inactive genes in the nucleus
__________
of a body cell to form
cells of all tissue
types.
stem cells have
• Adult and embryonic _________
the potential to produce cells needed to
replace damaged tissues.
Plants from from single cells
• New cells in plants specialise into cells
flowers
of roots, leaves or ________.
Unlike animal cells some plant cells
remain unspecialised
____________ and can
develop into any type of plant cell.
These unspecialised
cells allow the
clones
production of _______
of plants with desirable
features, from cuttings
_______.
Plant meristems
• Plant meristems divide to
produce cells that result
in increased
___________________
height, length of roots
and ______
girth of the plant.
If the hormonal conditions in their environment are
changed, unspecialised plant cells can develop into a range
xylem and phloem
of other tissues (eg _____________________)
or organs (eg
leaves, roots, flowers
____________________)
Plant Hormones
roots in the
Cut stems from a plant can develop _______
auxins and grow into a
presence of plant hormones (________)
clone of the parent
complete plant which is a _______
Phototropism
the plant’s response to light
Phototropism is _________________________.
survival
It increases the plant’s chance of _________.
auxin to move to the opposite side of
Light causes ______
the shoot tip. The cells on the side with more auxin
bigger
grow ______.
Questions
two cells.
Division of a cell by mitosis creates ____
When do mammalian embryonic cells become
specialised? The eight cell stage
How do cells control which proteins they
produce?
They can inactivate genes or reactivate inactivated genes.
If animal stem cells can produce cells to
replace damaged tissues, what can plant stem
cells do? Develop into any type of plant cell