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Mind Map by Noor Sohail, updated more than 1 year ago
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Created by hchen8nrd
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Copied by Noor Sohail
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Edexcel
Additional
Science
Biology Topic
1
- Cells and
Microscopy
- plant cells
- cell membrane
rigid cell walls
large vacuole
chloroplasts
mitochondria
nucleus
cytoplasm
- cell membrane
rigid cell walls
large vacuole
chloroplasts
mitochondria
nucleus
cytoplasm
- Animal Cell
- cell membrane
mitochondria
cytoplasm
nucleus
- cell membrane
mitochondria
cytoplasm
nucleus
- Bacteria Cell
- chromosomal
DNA plasmids
flagellum cell
wall
- chromosomal
DNA plasmids
flagellum cell
wall
- Microscopes
- light
microscopes
invented
1590s
- Electron
microscopes
invented
1930s
- magnification
=
Length
of
image/
length
of
specimen
- magnification
=
Length
of
image/
length
of
specimen
- Electron
microscopes
invented
1930s
- light
microscopes
invented
1590s
- plant cells
- DNA-
Deoxy-
ribo-
nucleic
Acid
- 4
Bases
- Adenine
Thymine
Guanine
Cytosine
- Pairings:
A+T
G+C
- Adenine
Thymine
Guanine
Cytosine
- A DNA molecule has 2
strands coiled together;
the shape of a double helix
- Base pairs are joined by
weak hydrogen bonds
- 3 bases = 1 codon/ 1 triplet
for a specific protein
- 3 bases = 1 codon/ 1 triplet
for a specific protein
- Base pairs are joined by
weak hydrogen bonds
- Rosalind
Franklin
and
Maurice
Williams-
worked
out DNA
had a
helical
structure
- They beams
of x-rays
onto
crystalised
DNA and
looking at
patterns the
x-rays
formed when
they bounced
off
- James Watson and Francis
Crick used RF's and MW's
ideas, along with knowledge
of the pairs to make a DNA
Model
- James Watson and Francis
Crick used RF's and MW's
ideas, along with knowledge
of the pairs to make a DNA
Model
- They beams
of x-rays
onto
crystalised
DNA and
looking at
patterns the
x-rays
formed when
they bounced
off
- Extracting
DNA
- Chop
Onion
- In beaker =
detergent +
salt
- water bath-
60 degrees-
15 minutes
- Beaker ->
Ice
- Cold ->
blender
- cool->
filter
- +ice cold
alcohol =
DNA
- +ice cold
alcohol =
DNA
- cool->
filter
- Cold ->
blender
- Beaker ->
Ice
- water bath-
60 degrees-
15 minutes
- In beaker =
detergent +
salt
- Chop
Onion
- 4
Bases
- Protein Synthesis
- Trans-
cription
- DNA unzips and one
strand is used as a
template to form mRNA
(base pairing ensures it's
an exact match)
- Thymine is replaced
with Uracil
- The mRNA molecule moves
out of the nucleus and joins
with a Ribosome
- TRANS-
LATION
- The ribosome reads the mRNA 1
codon at a time. Molecules called
tNRA then bring back to the
ribosome amino acids that match
- The ribosome sticks the
amino acids into a chain;
this is called a
POLYPEPTIDE
- this results in a protein,
with its own no. and
sequence of acids
- this results in a protein,
with its own no. and
sequence of acids
- The ribosome sticks the
amino acids into a chain;
this is called a
POLYPEPTIDE
- The ribosome reads the mRNA 1
codon at a time. Molecules called
tNRA then bring back to the
ribosome amino acids that match
- TRANS-
LATION
- Thymine is replaced
with Uracil
- DNA unzips and one
strand is used as a
template to form mRNA
(base pairing ensures it's
an exact match)
- Trans-
cription
- Mutations
- BAD
- Cause a
genetic
disorder- cystic
fibrosis./
change a
proteins shape
- Cause a
genetic
disorder- cystic
fibrosis./
change a
proteins shape
- GOOD
- produce new
characteristics
that is
beneficial e.g.
genes in
bacterial
plasmids can
make them
resistant to
anti-biotics
- produce new
characteristics
that is
beneficial e.g.
genes in
bacterial
plasmids can
make them
resistant to
anti-biotics
- Neutral
- some mutations
are neither
harmful or
beneficial e.g.
they don't
affect a
proteins
function
- some mutations
are neither
harmful or
beneficial e.g.
they don't
affect a
proteins
function
- BAD
- Enzymes
- enzymes are
catalysts
produced by
living things. a
catalyst is a
substance
which
increases the
speed of a
reaction
without being
changed or
used up in the
reaction.
- examples
of
enzyme
catalysed
reactions
- DNA
replication
protein
synthesis
digestion
- DNA
replication
protein
synthesis
digestion
- LOCK
AND
KEY
THEORY
- enzymes have
special shapes so
they can catalyse
reactions
- The enzyme has an
active site which
fits the shape of
the substrate (the
molecule being
changed); the
enzyme has a
specificity for
their substrate
- Enzyme active
site = lock
- the active site catalyses the
reaction of the substrate,
creating products. the enzyme
is unchanged.
- temperature will
affect enzyme.
increasing it will
increase the reaction
to a point; the
enzymes have more
energy. once it's too
hot, the bonds
holding the enzyme
breaks; the enzyme
loses its shape and
doesn't fit the
substrate. The
enzyme is denatured.
- optimum temp for most
human enzymes - 37
degrees
- Factors Affecting Enzymes
- optimum temp for most
human enzymes - 37
degrees
- pH also has an effect. too high or too
low and the enzyme will denature
- substrate concentrations will
increase the rate of reaction to a
point
- substrate concentrations will
increase the rate of reaction to a
point
- temperature will
affect enzyme.
increasing it will
increase the reaction
to a point; the
enzymes have more
energy. once it's too
hot, the bonds
holding the enzyme
breaks; the enzyme
loses its shape and
doesn't fit the
substrate. The
enzyme is denatured.
- the active site catalyses the
reaction of the substrate,
creating products. the enzyme
is unchanged.
- substrate
=
Key
- Enzyme active
site = lock
- The enzyme has an
active site which
fits the shape of
the substrate (the
molecule being
changed); the
enzyme has a
specificity for
their substrate
- enzymes have
special shapes so
they can catalyse
reactions
- examples
of
enzyme
catalysed
reactions
- enzymes are
catalysts
produced by
living things. a
catalyst is a
substance
which
increases the
speed of a
reaction
without being
changed or
used up in the
reaction.
- The Human Genome
Project
- 1000s of scientists collaborated to try
and find every single human gene;
about 25 000. The collaboration
meant all the genes were found
quickly and data could be made
public
- Positives
- predict and prevent
diseases
- develop new and better medicines
- accurate diagnosis
- improve forensic science
- predict and prevent
diseases
- Negatives
- Increased stress from
people with faulty
genes
- Gene-ism people with
genetic problems
pressured to not have
chidren
- Discrimination from
employers and
insurance companies
- Increased stress from
people with faulty
genes
- Positives
- 1000s of scientists collaborated to try
and find every single human gene;
about 25 000. The collaboration
meant all the genes were found
quickly and data could be made
public
- Genetic Engineering
(GE-Genetically engineered)
- uses enzymes to cut and paste
genes
- restriction
enzymes cut
out the
useful gene
- lysozyme
enzymes cut a
section out of
a bacterial
plasmid
- the useful gene is inserted into the
bacterial plasmid and ligase enzymes join
up the ends of DNA
- the plasmid is inserted into new
bacterial cell; it is now a vector
for the gene and has recombiant
DNA
- Benefits
- Reducing vitamin A deficiency.
GE rice produces BETA
CAROTENE which is used to
make VA. it has 2 GE genes
- quickly and cheaply produces
human insulin for diabetics
- Increasing Crop Yield-
resistant to herbicides
etc.
- Reducing vitamin A deficiency.
GE rice produces BETA
CAROTENE which is used to
make VA. it has 2 GE genes
- Controversy
- reduces farmland
biodiversity
- GM crops might be
unsafe- people
develop allergies
- Genes get into the natural
environment- super weeds that
are resistant to herbicides
- reduces farmland
biodiversity
- Benefits
- the plasmid is inserted into new
bacterial cell; it is now a vector
for the gene and has recombiant
DNA
- the useful gene is inserted into the
bacterial plasmid and ligase enzymes join
up the ends of DNA
- restriction
enzymes cut
out the
useful gene
- uses enzymes to cut and paste
genes
- MITOSIS
- Mitosis makes
new cells for
growth and repair;
it is asexual
- 1. inside the cell the
nuclear envelope breaks
and the chromosomes
duplicate into pairs
- 2. the pairs line up along
the equator of the cell
inbetween the 2 opposite
poles
- 3. spindles/ cell fibres form
from the poles and attach to the
arms of the chromosomes; the
pull the pairs apart so each pole
has its own copy
- 4.membranes form around
each set of chromosomes,
they become the nuclei of
the 2 new cells
- .5. the cytoplasm
divides and you
have 2 genetically
identical diploid
daughter cells
- .5. the cytoplasm
divides and you
have 2 genetically
identical diploid
daughter cells
- 4.membranes form around
each set of chromosomes,
they become the nuclei of
the 2 new cells
- 3. spindles/ cell fibres form
from the poles and attach to the
arms of the chromosomes; the
pull the pairs apart so each pole
has its own copy
- 2. the pairs line up along
the equator of the cell
inbetween the 2 opposite
poles
- 1. inside the cell the
nuclear envelope breaks
and the chromosomes
duplicate into pairs
- Mitosis makes
new cells for
growth and repair;
it is asexual
- MEIOSIS
- meiosis only occurs sexual reproduction
organs- testes and ovaries and it involves 2
divisions
- 1. the DNA duplicates into
pairs of chromosomes, each
arm is identical to the
other
- 2. alike pairs line up on the
equator and share genetic
codes. the chromosome
pairs are pulled apart. each
new cell now has some
chromosomes from the
mum and some from dad.
mixing the alleles creates
genetic variation
- 3.. in the 2 new cells the
chromosomes line up again
and spindles form, pulling
the arms of the pairs of
chromosomes apart
- 4. membranes form around
each of the 4 sets of
chromosomes becoming the
nucleus
- 5. the cytoplasm splits. You
now have 4 haploid daughter
cells, they are genetically
different
- Gametes are another word for
sex cells- when 2 gametes
combine a fertilised egg is
called a zygote
- Gametes are another word for
sex cells- when 2 gametes
combine a fertilised egg is
called a zygote
- 5. the cytoplasm splits. You
now have 4 haploid daughter
cells, they are genetically
different
- 4. membranes form around
each of the 4 sets of
chromosomes becoming the
nucleus
- 3.. in the 2 new cells the
chromosomes line up again
and spindles form, pulling
the arms of the pairs of
chromosomes apart
- 2. alike pairs line up on the
equator and share genetic
codes. the chromosome
pairs are pulled apart. each
new cell now has some
chromosomes from the
mum and some from dad.
mixing the alleles creates
genetic variation
- 1. the DNA duplicates into
pairs of chromosomes, each
arm is identical to the
other
- meiosis only occurs sexual reproduction
organs- testes and ovaries and it involves 2
divisions
- Cloning
- cloning is a type of asexual
reproduction; it produces cells that
are genetically identical to the
original
- 1. enucleate an unfertilised egg cell -
remove the nucleus
- 2. take a diploid nucleus from an
adult body cell and insert it into the
enucleated egg cell
- 3. stimulate the egg cell with an
electric shock; the cell will start
dividing by mitosis
- 4. when the embryo is a ball of cells,
implant it into an adult female (a
surrogate)
- Uses
- help with the shortage of
organs for transplants
- study of clones could lead to
a greater understanding of
the embryo and ageing/ age
related disorders
- preserve endangered species
- help with the shortage of
organs for transplants
- Issues
- closely related populations
will be wiped out by new
diseases; there may be no
allele giving resistance
- cloned animals might not
live as long
- cloning often fails
- clones are often born with
defects and weak immune
systems
- reduced gene pool
- closely related populations
will be wiped out by new
diseases; there may be no
allele giving resistance
- Uses
- 4. when the embryo is a ball of cells,
implant it into an adult female (a
surrogate)
- 3. stimulate the egg cell with an
electric shock; the cell will start
dividing by mitosis
- 2. take a diploid nucleus from an
adult body cell and insert it into the
enucleated egg cell
- 1. enucleate an unfertilised egg cell -
remove the nucleus
- cloning is a type of asexual
reproduction; it produces cells that
are genetically identical to the
original
- Stem Cells
- cells in an embryo are all the same-undifferentiated.
they are called embryonic stem cells
- stem cells are able to divide to produce specialised
cells or more stem cells. the process of becoming
specialised is called differentiation
- in most animal cells, the ability to differentiate is lost
at a early stage; plants never lose this ability
- adult stem cells only occur in certain places like bone
marrow; they aren't as versatile- multipotent. there is
a limit to what they can differentiate into. embryonic
stem cells are pluripotent
- Pro- adult stem cells are already
used to cure some diseases -
sickle cell anaemia
- could be possible to use
embryonic stem cells to replace
cells damaged from injury/
disease.
- Arguments against- embryos are
a source of life
- Arguments against- embryos are
a source of life
- could be possible to use
embryonic stem cells to replace
cells damaged from injury/
disease.
- Pro- adult stem cells are already
used to cure some diseases -
sickle cell anaemia
- adult stem cells only occur in certain places like bone
marrow; they aren't as versatile- multipotent. there is
a limit to what they can differentiate into. embryonic
stem cells are pluripotent
- in most animal cells, the ability to differentiate is lost
at a early stage; plants never lose this ability
- stem cells are able to divide to produce specialised
cells or more stem cells. the process of becoming
specialised is called differentiation
- cells in an embryo are all the same-undifferentiated.
they are called embryonic stem cells
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