5025098
Description
Mind Map by Pritesh Patel, updated more than 1 year ago
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Created by Pritesh Patel
about 8 years ago
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OCR 21st Century B5
- Growth and Development
- Protein
Synthesis
- Adenine-Thymine
- Guanine-Cytosine
- Uracil-A
in
MRNA
- Guanine-Cytosine
- A protein is a chain of amino acids. The
sequence of amino acids produces
different proteins.There are many
thousands of different sequences
- Firstly the gene unzips and mRNA moves in to the nuclear membrane (through the pores
as it is able to fit). The mRNA bases pair with the DNA bases to form a strand of mRNA
- The RNA moves out of the nucleus and into the cytoplasm. There it finds a ribosome
- The ribosome attaches to one end of the mRNA. As it moves along the mRNA it reads the
bases in groups of three (triplet code/codon). Each codon codes for a single amino acid.
- Different combinations of the
four bases produces 64 triplet
codes. So there is more than
one code for each amino acid.
- The ribosome reads the genetic code so that it can join the amino acids together in the correct order
- When it has finished, the ribosome releases the protein into the cytoplasm and starts to make another one
- When it has finished, the ribosome releases the protein into the cytoplasm and starts to make another one
- Different combinations of the
four bases produces 64 triplet
codes. So there is more than
one code for each amino acid.
- The ribosome attaches to one end of the mRNA. As it moves along the mRNA it reads the
bases in groups of three (triplet code/codon). Each codon codes for a single amino acid.
- The RNA moves out of the nucleus and into the cytoplasm. There it finds a ribosome
- Firstly the gene unzips and mRNA moves in to the nuclear membrane (through the pores
as it is able to fit). The mRNA bases pair with the DNA bases to form a strand of mRNA
- Gene
Switching
- Although all body cells in an
organism contain the same
genes, many genes in a
particular cell are not active
(switched off) because the cell
only produces the specific
proteins it needs
- Understand that in
specialised cells only the
genes needed for the cell
can be switched on, but in
embryonic stem cells any
gene can be switched on to
produce any type of
specialised cell.
- In carefully controlled
conditions of mammalian
cloning, it is possible to
switch on inactive genes in
the nucleus of a body cell to
form cells of all tissue types.
- ethical decisions need to
be taken when using
embryonic stem cells
- 1.nucleus taken out of a human egg cell 2. nucleus from a patient's cell put into the egg cell 3. egg cell stimulated to develop into an embryo 4. stem
cells taken from the embryo 5. stem cells grown in a container of warm nutrients 6. stem cells treated to develop into required cell types
- ethical decisions need to
be taken when using
embryonic stem cells
- Understand that in
specialised cells only the
genes needed for the cell
can be switched on, but in
embryonic stem cells any
gene can be switched on to
produce any type of
specialised cell.
- Although all body cells in an
organism contain the same
genes, many genes in a
particular cell are not active
(switched off) because the cell
only produces the specific
proteins it needs
- Adenine-Thymine
- Protein
Synthesis
- Cell Specialisation
- Multicellular
organisms
- each kind of cell is
specialised to perform
particular jobs
- groups of specialised cells
are called tissues, and groups
of tissues form organs
- a fertilised egg cell
(zygote) divides by
mitosis to form an
embryo (a ball of
about 100 cells)
- In a human embryo up to (and including) the eight cell
stage, all the cells are identical (embryonic stem cells) and
could produce any type of cell required by the organism
- After this stage, most of
the embryonic stem
cells are specialised
- After this stage, most of
the embryonic stem
cells are specialised
- In a human embryo up to (and including) the eight cell
stage, all the cells are identical (embryonic stem cells) and
could produce any type of cell required by the organism
- a fertilised egg cell
(zygote) divides by
mitosis to form an
embryo (a ball of
about 100 cells)
- groups of specialised cells
are called tissues, and groups
of tissues form organs
- Adult stem cells remain unspecialised and can
become specialised at a later stage but cannot
become any type of cell mainly blood cells
- both these and embryonic
stem cells have the potential
to produce cells needed to
replace damaged tissues
- both these and embryonic
stem cells have the potential
to produce cells needed to
replace damaged tissues
- each kind of cell is
specialised to perform
particular jobs
- Plants
- Only meristem cells
are mitotically active
- Unspecialised
cells
- Cells specialise to form different types
of tissue (including xylem and phloem)
within organs (including flowers, leaves,
stems and roots
- Found in, shoot tips,
root tips, and in
rings (stem/roots)
to increase girth
- Found in, shoot tips,
root tips, and in
rings (stem/roots)
to increase girth
- Cells specialise to form different types
of tissue (including xylem and phloem)
within organs (including flowers, leaves,
stems and roots
- Unspecialised
cells
- The presence of meristems allows the production of clones
of a plant from cuttings. Cuttings are taken because they
can be produced quickly and cheaply. Due to them being
clones, a farmer can produce a plant with desired features.
- The cuttings are placed in rooting
powder which contains the plant
hormone-auxin. This stimulates
the meristems to divide thus
producing a root system, allowing
the cutting to be planted.
- The cuttings are placed in rooting
powder which contains the plant
hormone-auxin. This stimulates
the meristems to divide thus
producing a root system, allowing
the cutting to be planted.
- Only meristem cells
are mitotically active
- Phototropism
- The bending of
growing plant
shoots towards
the light
- By doing this a plant increases its
chance of survival. This is because
it is able to absorb more light
which it uses for photosynthesis to
produce glucose (food).
- Auxins are hormone that
grow near tips of shoots
and roots. They diffuse
backwards to stimulate
cell elongation
- When a shoot tip is exposed to light, more auxins
accumulate on the shady side (via diffusion). They
stimulate meristems to divide and cause growth
at an increased rate on the shaded side so that
the plant bends towards the light
- When a shoot tip is exposed to light, more auxins
accumulate on the shady side (via diffusion). They
stimulate meristems to divide and cause growth
at an increased rate on the shaded side so that
the plant bends towards the light
- Auxins are hormone that
grow near tips of shoots
and roots. They diffuse
backwards to stimulate
cell elongation
- By doing this a plant increases its
chance of survival. This is because
it is able to absorb more light
which it uses for photosynthesis to
produce glucose (food).
- The bending of
growing plant
shoots towards
the light
- Multicellular
organisms
- Cell Cycle
- B. Mitosis
- A type of cell division which
Produces two new cells that are
genetically identical to each
other and to the parent cell.
- Growth and repair is
dependent on mitosis
- Asexual reproduction
takes place via mitosis
- During Mitosis
copies of
chromosomes
separate and the
whole cell divides
- During Mitosis
copies of
chromosomes
separate and the
whole cell divides
- Asexual reproduction
takes place via mitosis
- copies of the chromosomes
separate & the nucleus divides
- Growth and repair is
dependent on mitosis
- A type of cell division which
Produces two new cells that are
genetically identical to each
other and to the parent cell.
- A. Cell
Growth
- Weak Hydrogen bonds between the
bases split, unzipping the DNA from
one end to form two strands
- Immediately,
new strands start
to form from free
bases in the cell
- As A-T and
C-G, the
two new
chains are
identical
- This process shows how the chromosomes copy themselves.
Secondly, before a cell can divide, it must also grow and
make copies of organelles (ribosomes and mitochondria)
- This process shows how the chromosomes copy themselves.
Secondly, before a cell can divide, it must also grow and
make copies of organelles (ribosomes and mitochondria)
- As A-T and
C-G, the
two new
chains are
identical
- Immediately,
new strands start
to form from free
bases in the cell
- Weak Hydrogen bonds between the
bases split, unzipping the DNA from
one end to form two strands
- Meiosis
- a type of cell
division that
produces
gametes
- produces four
genetically
different
haploid cells
- a zygote contains
a set of
chromosomes
from each parent
- 23
chromosomes
- Genetic variation is as a result of
crossing over before meiosis.
- a zygote contains
a set of
chromosomes
from each parent
- produces four
genetically
different
haploid cells
- a type of cell
division that
produces
gametes
- B. Mitosis
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