Biology done b.1,b.4,b.5 Flashcards
1
Q
What has Eukaryotic cells animals and plants or bacteria
A
animas and plants
2
Q
What are prokaryotes
A
simple cells found in bacteria
3
Q
What’s the job of the nucleus
A
contains DNA in the form of chromosomes that control the cells activity
4
Q
What’s cytoplasm
A
gel-like substance where most of the chemical reactions happen
5
Q
What’s the job of the mitochondria
A
site of cellular respiration and contain the enzymes needed for the reactions involved
6
Q
What’s the cell membrane
A
holds the cell together and controls what goes in and out they also contain receptor molecules that are used for cell communication
7
Q
What’s ribosomes
A
where proteins made in the cell
8
Q
What’s the cell wall made out of and what’s its job
A
made of cellulose and gives support for the cell
9
Q
What’s the job of the chloroplast
A
where photosynthesis occurs. they contain called chlorophyll
10
Q
What’s the difference between the DNA storage in prokaryotic and eukaryotic cells
A
prokaryotic cells is one long circular chromosome and other floats free in the cytoplasm
11
Q
What are plasmids
A
small loops of extra DNA that aren’t part of the chromosome
12
Q
What do plasmids contain
( think genes )
A
they contain genes for things like drug resistance and can be passed between bacteria
13
Q
Do prokaryotic cells have a cell wall
A
they do it supports the cell membrane
14
Q
What do light microscopes let us see
A
bacteria and mitochondria and nuclei and chloroplast
15
Q
What’s the job of the eyepiece on a light microscope
A
to look through and magnify image
16
Q
What do electron microscopes let us see
A
things smaller than a light microscopes and giving us a better understanding of sub cellular structure
17
Q
What’s the job of the objective lens
A
magnifies the image it usually has 3 objective lenses x4, x10 and x40
18
Q
What’s the job of the stage
(microscopes)
A
support the slide
19
Q
What’s the job of the clip
A
hold the slide in place
20
Q
What’s the job of the lamp
A
shine light through the slide
21
Q
What’s the job of the focussing knobs
A
move the stage up and down to bring image into focus
22
Q
What’s the formula to get the total magnification
A
total magnification= eyepiece lens magnification x objective lens magnification
23
Q
What’s the formula for magnification
A
magnification = image size ÷ real size
24
Q
What’s DNA
A
the chemical that makes up the genetic material of organisms
25
What are chromosomes
long molecules of coiled up DNA.
26
What does DNA stand for
deoxyribonucleic acid
27
What are genes
a section of DNA which controls part of a cell's chemistry - particularly protein production
28
How many bases does DNA have
4
29
What are DNAs bases
adenine (A), cytosine (C), guanine (G), and thymine (T).
30
What are the pairs if the bases
A and T
C and G
31
What's RNA
Ribonucleic acid
32
What's nucleotide
the basic building block of nucleic acids (RNA and DNA
33
What does sugar and phosphate do
joins together nucleotides in a DNA sequence
34
What are polymers
they are long chains of monomers joined together
35
What are monomers
small molecular units
36
DNA is a polymer made up of nucleotide monomers
TRUE or FALSE
true
37
What's metabolism
reactions occurring in the cell like photosynthesis, respiration and protein synthesis
38
Are enzymes biological catalysts
True or False
true
39
What would raising the temperature do to enzymes
speed up reactions
40
Why is rising the temperature bad for enzymes
it speeds up unwanted reactions and it would damage the cells
41
How many reactions have there own enzymes
Every one
42
What do chemical reactions involve
things being split apart or joined together
43
What's a substrate
the molecule changed in the reaction
44
What happens in the enzymes active site
the part it joins to its substrate to catalyze the reaction
45
How many substrates do enzymes USUALLY work with
1
they have a high specificity for there substrate
46
What's the lock key hypothesis for enzymes
The enzyme has a specific active site that fits the substrate exactly just like a key fits into a specific lock
47
The steps of the lock and key hypothesis (enzymes)
1. Enzyme and Substrate Encounter
The enzyme's active site (the "lock") has a specific shape that matches the shape of the substrate (the "key").
The substrate approaches the enzyme.
2. Formation of the Enzyme-Substrate Complex
The substrate binds to the enzyme at the active site, forming the enzyme-substrate complex.
This interaction is highly specific, as only the correct substrate can fit into the enzyme's active site.
3. Catalysis
The enzyme catalyzes the reaction, converting the substrate into the product(s).
This occurs while the substrate is bound to the enzyme, often by lowering the activation energy required for the reaction.
4. Release of Product(s)
Once the reaction is complete, the product(s) no longer fit the active site and are released.
The enzyme remains unchanged and is free to catalyze another reaction with a new substrate.
48
What does changing the temperature do to an enzyme controlled reaction
changes the rate of it
49
Why does increasing the temperature increase the rate if an enzme reaction
the substrates move about more so are more likely to meet up and react
50
What happens to enzymes bonds if the temperature get to hot
they break
51
What does denatured mean with enzymes
it looses its shape and the substrate doesn't fit the active sight any more
52
What does denaturing result in for the reaction
it can't be catalysed and the reaction stoped
53
Is denaturing for enzymes reversible
no so even if you cool it down again it won't return to original shape
54
Do enzymes have an optimal temperature
yes they do this is the temperature where the reaction is at its fastest
55
Wasted the optimum temperature for enzymes in humans
37 degrees c
56
What does the pH affect in enzymes
If to high or low this interferes with the bonds this changes the shaper of the activation site
57
What's the activation sight
the part of an enzyme where a substrate molecule binds and a chemical reaction occurs
58
What's the optimum pH for most enzymes
pH of 7 however not all work best at this pH
59
What does increasing the concentration of enzyme molecules do to the rate of reaction and why
increase the ror as its more likely a substrate will meet one and join with it
60
Does the concentration of enzyme molecules up to one point and why
it only increases the rate of reaction to a certain point as there are more substrate molecules than the enzymes can cope with meaning that the active sites are full so adding more makes no difference
61
What's respiration
the process of transfering energy from the breakdown of glucose
62
Where does respiration happen
in cells all the time
63
How id the energy transferred by respiration used
makes a substance called ATP
64
What does ATP do
it stores the energy required for cell processes and releases it
65
What is respiration controlled by
enzymes
66
What can affect respiration if it is controlled by enzymes
temperature and pH
67
is respiration an exo or endothermic reaction
exothermic
68
Why is respiration for an exothermic reaction
it transfers heat to the environment by heat
69
How can cells respire
using glucose as a substrate but organisms can also breakdown other organic molecules to use as substrates for respiration
70
What is aerobic respiration
where there is plenty of oxygen available to be used
71
How much ATP does aerobic respiration produce
32 molecules per molecules of glucose
72
What's the equation for aerobic respiration (word and symbol)
glucose + oxygen → carbon dioxide + water + energy
C6H12O6 + 6O2 → 6CO2 + 6H2O
73
What's anaerobic respiration
a chemical process that occurs in cells when food is broken down to produce energy without oxygen
74
Why is anaerobic respiration less efficient than aerobic respiration
it transfers less energy per glucose molecule
75
How much ATP does anaerobic respiration create
2 molecules of ATP are produced
76
What happens during anaerobic respiration in animals and why does this happen
In anaerobic respiration, glucose is partially broken down to produce lactic acid. This happens when the body cannot supply enough oxygen to the muscles
77
What is the word and symbol equation for anaerobic respiration in animals
Glucose → Lactic Acid
C6H12O6 → 2C3H6O3 + energy
78
Why do muscles become fatigued during vigorous exercise
Lactic acid builds up in the muscles, causing pain and muscle fatigue
79
What is an oxygen debt
Oxygen debt is the amount of oxygen required to break down lactic acid after exercise. This is why you breathe hard after stopping vigorous activity
80
What is the advantage of anaerobic respiration
Anaerobic respiration allows the muscles to keep working when oxygen is limited
81
What's an example of where plants will anaerobicly respire
waterlogged soil
82
What is an example of a fungi that anaerobicly respire
yeast
83
Products of aerobic respiration
Carbon dioxide and water
84
Products of anaerobic respiration in animals
lactic acid
85
Products of anaerobic respiration in some fungi
ethanol and carbon dioxide
86
What can be broken down so that energy can be transferred to ATP through respiration
carbohydrates, proteins and lipids
87
Carbohydrates molecules contain what elements
carbon hydrogen and oxygen
88
Examples of monomers that carbohydrates are made up of
glucose and fructose molecules
89
How can the polymer molecules be broken back to sugars
when the chemical bonds between the monomers are broken
90
How are carbohydrates broken down in the body
enzymes in the mouth and the small intestine
91
Why are proteins polymers
because they are made up of long chains of monomers
92
What monomers are proteins made up of
amino acids
93
What atoms do amino acids contain
carbon, nitrogen, hydrogen and oxygen
94
What are lipids
fats and oils
95
What are lipids made up of
glycerol and 3 fatty acids
96
What is glycerol
a colorless, odorless, viscous, liquid, polyol compound
97
Why aren't lipids polymers
because they do not form a long chain of repeating units
98
What atoms do lipids contain
carbon hydrogen and oxygen
99
How are lipids broken down in the body
enzymes in the small intestine
100
How does photosynthesis happen
Light absorption
Chlorophyll, a green substance in chloroplasts, absorbs light energy from the sun.
Water splitting
Energy is used to split water molecules into hydrogen and oxygen. The plant releases the oxygen as a waste product.
Carbon dioxide fixation
Hydrogen is combined with carbon dioxide to make glucose.
Chemical energy storage
The glucose is converted into other substances, like starch and plant oils, which store energy. The plant can release this energy through respiration.
101
What is some of the glucose made in photosynthesis used for
to make more complex molecules that allow the plant or algae to grow
102
photosynthesis word and symbol equation
Carbon dioxide + water → oxygen + glucose
6CO2 + 6H2O → C6H12O6 + 6O2
103
Is photosynthesis an end or exothermic reaction
endothermic because energy is transferred from the environment during it
104
What are the 2 main stages of photosynthesis
energy transferred by light the energy is then used to split water into oxygen gas and hydrogen ions
Carbon dioxide gas then combines the hydrogen ions to make glucose
105
What are the two factors of recycling materials in an ecosystem
abiotic and biotic
106
How do living things recycle elements in the atmosphere (step by step)
1)
Living things are made of elements they take from the environment.
For example, plants take in carbon, hydrogen, oxygen, nitrogen, etc.
2)
They turn these elements into the complex compounds (carbohydrates, proteins and fate) that make up living organisms. These are taken in by animals when they eat the plants.
3)
The elements are recycled — they return to the environment (e.g. soil or air) through waste products or when organisms die, ready to be used by new plants and put back into the food chain.
4)
Dead organisms and waste products decay because they're broken down by decomposers (usually microorganisms) — that's how the elements get put back into the soil.
107
The cabin cycle (step by step)
1) There's only one arrow going down from CO2, in the air. The whole thing is 'powered" by photosynthesis.
Green plants use the carbon from CO2, in the air to make carbohydrates, fats and proteins.
2)
Eating passes the carbon compounds in the plant along to animals that eat them.
3) Both plant and animal respiration while the organisms are alive releases CO2, back into the air.
4) Plants and animals eventually die and decompose, or are killed and turned into useful products.
5) When plants and animals decompose they're broken down by microorganisms, such as bacteria and fungi These decomposers release CO2, back into the air by respiration, as they break down the material.
6) Some useful plant and animal products, e.g. wood and fossil fuels, are burned (combustion).
This also releases CO2
back into the air.
7) Decomposition of materials means that habitats can be maintained for the organisms that live there. e.g. nutrients are returned to the soil and waste material, such as dead leaves, doesn't just pile up.
108
The nitrogen cycle
1)
The atmosphere contains 78% nitrogen gas, N2. This is very unreactive and so it can't be used directly by plants or animals. Nitrogen is needed for making proteins for growth, so living organisms have to get it somehow.
2) Plants get their nitrogen from the soil, so nitrogen in the air has to be turned into nitrates before plants can use it. Nitrogen compounds are then passed along food chains as animals eat plants (and each other).
3)
Decomposers (bacteria and fungi in the soil) break down proteins in rotting plants and animals, and urea in animal waste, into ammonia, which goes on to form ammonium ions. This returns the nitrogen compounds to the soil - so the nitrogen in these organisms is recycled.
4) Nitrogen fixation is the process of turning from the air into nitrogen compounds
in the soil which plants can use.
There are two main ways that this happens:
a) Lightning — there's so much energy in a bolt of lightning that it's enough to make nitrogen react with oxygen
fying
¿teria
in the air to give nitrates.
b) Nitrogen-fixing bacteria in roots and soil (see below).
Nitrates in the so
5) There are four different types of bacteria involved in the nitrogen cycle:
a) DECOMPOSERS — decompose proteins and urea and turn them into ammonia, which goes on to form ammonium ions.
b) NITRIFYING BACTERIA - turn ammonium ions in decaying matter into nitrates.
c) NITROGEN-FIXING BACTERIA - turn atmospheric N, into nitrogen compounds that plants can use.
d) DENITRIFYING BACTERIA - turn nitrates back into N, gas. This is of no benefit to living organisms.
Denitrifying bacteria are often found in waterlogped soils
6)
Some nitrogen-fixing bacteria live in the soil. Others live in nodules on the roots of legume plants (e.g. peas and beans). This is why legume plants are so good at putting nitrogen back into the soil.
The plants have a mutualistic relationship with the bacteria — the bacteria get food (sugars) from the plant, and the plant gets nitrogen compounds from the bacteria to make into proteins.
So the relationship benefits both of them.
109
The water cycle (step by step)
1) The Sun makes water evaporate from the land and sea, turning it into water vapor Water also evaporates from plants via transpiration
2) The warm water vapor is carried upwards (as warm air rises ), When it gets higher up it cools and condenses to from clouds
3) Water falls from the clouds as precipitation (usually rain, but
sometimes snow or hail) and is returned to the land and sea.
4) The flow of fresh water through the water cycle allows nutrients to be transported to different ecosystems
110
What are the different ecosystem levels
Individual
Population
Community
Ecosystem
111
What do plants compete for to survive
light
space
water
minerals (nutrients)
112
What do animals compete for to survive
territory
food
water
mates
113
What's an effect of competition among different species
population decline
114
Is environment change an abiotic or biotic factor
abiotic
115
List three abiotic factors affects on communities
temperature
moisture level
light intensity
pH
116
Name two biotic factors affects on communities
availability of food
number of predators
117
How does the population of prey and predators link
If the number of prey increases so will the predators
however if population of predators increase the prey will decrease
118
What does the predator-prey cycle show about there relationship
how they are interdependent on each other
119
Why are predator prey cycles always out of phase
takes along time for the other species to respond
120
Examples of parasites
tapeworms
fleas
121
Examples of mutualism
clownfish
plants and bees
122
What's a parasite
a living organism that lives on or in another organism, called the host, and feeds off of it
123
What is a mutualism
a symbiotic relationship where two or more species benefit from each other's actions
124
What's a genome
the entire genetic material of an organism
125
What's a chromosome
a long molecule that contains DNA
126
What is a gene
a short length of a chromosome
127
What's a genes job
to determine the production of proteins
128
How does a gene determine the type of protein produced
Each triplet of bases codes for one particular amino acid
129
What are the different versions of the same gene called
alleles
130
What are the differences in the same species called eg:different hair color or shaped noses
variation within a species
131
Variation can be genetic what does this mean it is caused by
differences in genotype
132
What's a genotype
all the genes and alleles that an organism has
133
What affects an organisms phenotype
genotype
134
What's a phenotype
the characteristics that an organism displays
135
How can environment influence a plants phenotype related to sunlight
if it grew in sun it would grow Lucious but if it was in the shade it would grow tall and spindly and the leaves would turn yellow
136
How is most variation in phenotype determined
a mixture of genetic and environmental factors
137
An example of a mixture of genetic and environmental factors is maximum height explain how each one affects the plant
the maximum height is determined by genes and if will actually grow to that height is determined by the environment
138
What's continuous variation
when the individuals in a population vary within a range (the are no distinct catagories)
139
What's an example of continuous variation
human height or number of leaves on a tree
140
Characteristics that are usually influenced by more than one gene or by both genetic and environmental factors usually show what type of type of variation
continuous
141
What is an example of discontinuous variation
human blood groups
142
What is discontinuous variation
when there are two or more distinct categories each individual falls into
143
Characteristics influenced by one gene and that aren't influenced by the environment are what type of variation
discontinuous
144
What's a mutation
a rare random change in an organism's DNA that can be inherited
145
What results in a mutation
a sequence of DNA bass in the gene that has been changed which produces a genetic variant
146
What's a genetic variant
a different form of the gene
147
As the sequence of DNA bases in a gene codes for the sequence of amino acids that make up a protein, gene mutations sometimes lead to changes in what
the protein that it codes for
148
True or false that most mutations have no/little affect on the organisms phenotype
true
149
An example of a mutation having little affect on the organisms phenotype
a mutation in one gene leading to a small characteristic change like eye color
150
An example of a mutation having a large affect on the organisms phenotype
The genetic disorder, cystic fibrosis, can be caused by the deletion of just three bases but it has a huge effect on phenotype. The gene codes for a protein that controls the movement of salt and water into and out of cells. However, the protein produced by the mutated gene doesn't work properly. This leads to excess mucus production in the lungs and digestive system, which can make it difficult to breathe and to digest food.
151
What is sexual reproduction (think genetics)
where two organisms are combined to produce offspring which are genetically different to either parent
152
What's gametes
a reproductive cell of an animal or plant
153
What are the gametes in animals
sperm and egg cells
154
Gametes only contain half the number of chromosomes of normal cells what what is this called
haploid
155
Normal cells with the full number of chromosomes are called what
diploid
156
What happens to the male gamete and the female gamete and what does the haploid become
they fuse and it becomes a diploid
157
What is the process called when the fertilized egg cell divides
mitosis
158
True or false the embryo inherits characteristics from both parents as it has received a mixture of chromosomes and therefore its genes are from its mom and dad
True
159
What's meiosis
a process where a single cell divides twice to produce four cells containing half the original amount of genetic information
160
In humans where's the only place meiosis happens
reproductive organs
161
What happens in division 1 of meiosis
in the first division in meiosis the chromosomes line up in pairs in the centre of the cell.
One chromosome in each pair came from the organism's mother and one came from its father.
The pairs are then pulled apart, so each new cell only has one copy of each chromosome. Some of the father's chromosomes and some of the mother's chromosomes go into each new cell.
Each new cell will have a mixture of the mother's and father's chromosomes. Mixing up the genes like this is really important it creates genetic variation in the offspring.
162
What happens in division 2 of meiosis
In the second division the chromosomes line up again in the centre of the cell. It's a lot like mitosis. The arms of the chromosomes are pulled apart.
You get four haploid gametes - each only has a single set of chromosomes. The gametes are all genetically different.
163
How many pairs of chromosomes in human body
23 pairs
164
Males have what chromosomes
X and Y
the Y cause the male characteristics
165
Women have what chromosomes
XX
The lack of a Y chromosome causes the female characteristics
166
What type of sexual reproduction involves mitosis
Asexual reproduction
167
In asexual reproduction how many parents are there
1
168
What things reproduce asexually
Bacteria some plants and some animals
169
What are alleles
Different versions of the same gene
170
Whats a version of an allele
freckles or no freckles
171
Which version of an allele appears
The dominant
172
When will the recessive version of an allele show
If there's no dominant alleles/ both alleles are recessive
173
In genetic diagrams the dominant alleles are shown as what
The capital letter
174
In genetic diagrams the recessive alleles are shown as what
Lower case letter
175
Whats a homozygous trait
Both the same allele for that particular gene e.g. CC or cc (both dominant or both recessive)
176
Whats a heterozygous trait
Where there's 2 different alleles for that particular gene e.g. Cc (one recessive and one dominant)
177
Whats a genotype
The genes and alleles an organism has
178
Whats a phenotype
The characteristics an organism has
179
How do you classify organisms
Look at the differences and similarities between organisms and then we put them into classes
180
What are the 2 classification systems
Natural and artificial
181
What is artificial classification used for
To make keys so that scientists can easily identify and group animals
182
What is natural classification used for
To find information about classification system and common ancestors but also common structural systems
183
What are the kingdoms subdivided into
(the animal kingdom)
Phylum,class,order,family,genus,species
184
How does improvement in technology lead to advancements in classification
New discoveries and the relationships between organisms are being clarified
185
What is phylogentics
The study of how organisms are related to each other through evolution
186
Whats genetic variation
A big mix of gene variants (alleles) present in the population
187
How do variants arise
DNA randomly mutating
188
What are advantageous variants
A variation in a gene which is better suited for a certain environment
189
What is evolution
The change in inherited characteristics of a population through a process of natural selection
190
The speed of a species evolution depends on what
How fast it reproduces
191
Evolution can mean that a species phenotype can what
Develop so much that it can create a new species
192
How are fossils evidence for evolution
They show how organisms have changed over time and how species are related
193
How is bacteria evidence for evolution
It can become antibiotic resistance this shows how over time developments within genetic coding is possible
194
Distribution is
where an organism is found and how spread out it is
195
Whats abundance
How many individuals in an area
196
What is a pooter
Two tubes in a bung one for sucking the other vacuum's up a bug/insect
197
What is a pitfall
Container put in the ground and then place food in the container and then the bug will fall in it
198
What is a sweep net
Sweep the net across the long grass and then it should collect bugs
199
Quadrats are use to do what
Study the distribution of organisms
Place it down the quadrat count the number of organisms repeat and then repeat in random areas
200
How can you estimate the population of an organism
Scale up from a small sample area by working out the amount in one area and the x by the scalar for the full area
201
Whats the formula for capture recapture
population size =
(number in first sample x number in second sample) ÷ number in second sample already marked
202
Whats an abiotic factor for distribution of organisms
light intensity
ph of soup
temperature
moisture level
203
Whats a biotic factor for distribution of organisms
competition
204
How do you measure the abiotic factor temperature
Thermometer
205
How do you measure the abiotic factor light intensity
Light sensor
206
How do you measure the abiotic factor soil pH
pH monotors
207
Transects show what
How distribution of organisms change over a distance
Mark a straight line across a distance then use a quadrat and measure to check changes
208
Kite diagrams do what
Show abundance and distribution of multiple organisms over a distance
209
What are the different ways humans impact the environment
Higher population ending more land
Higher standard of living means we use more resources
More waste means there's more pollution
210
2 ways humans are destroying habitats
Deforestation
Monoculture- clearing an area to grow a single crop
211
Different Impacts of waste of land
Toxic chemicals aren't disposed properly and then they end up in land fill and harm the environment
Sewage alarms the natural water habitats
Smoke and gases pollute atmosphere
212
How is hunting dangerous to ecosystems
Can cause animals to be endangered and then they'll become extinct and disrupt the food chain and further decrease biodiversity
213
An example of protecting habitats
Controlling water levels to conserve wetlands and trimming trees to conserve woodlands to maintain habitats
214
4 ways maintain biodiversity helps all organisms
Protects human food supply
Minimal damage to food chains
Providing future medicines
Providing industrial materials and fuels
215
How is eco tourism good for biodiversity
The money made from the projects make it possible to pay to maintain the biodiversity
216
Difficulties of maintaining biodiversity
Agreements about these schemes can be challenging to agree upon because countries don't want to work together
Schemes can be difficult to monitor keeping track of fishing quotas for example make it easy to break the agreements
217
What is selective breeding
Breeding animals with a desired characteristic until they have offspring that then express the characteristic and it then becomes prominent in all offspring
218
Different characteristics wanted by selected breeding
Yield of milk and plants
Good health and disease resistance
Temperament
Looks and smell of flowers
219
Whats the steps of selective breeding
Decide which characteristics are important enough to select.
Choose parents that show these characteristics from a mixed population.
They are bred together. Choose the best offspring with the desired characteristics to produce the next generation.
Repeat.
220
An example of how selective breeding can be used to combine 2 characteristics
Tall plant with low yield mixed with dwarf plant with high yield
Cross breed and then the offspring becomes tall with high yield
221
Whats the main draw back of selective breeding
It reduces the gene pool and it reduces the amount of alleles and can eventually lead to inbreeding this can cause certain diseases and it reduces all genetic variation
222
Whats a vector
Something used to transfer DNA into a cell
223
Name a commonly used vector
Plasmids
224
The process of genetic engineering
Isolation of Gene – The desired gene is cut from DNA using restriction enzymes, which create sticky ends (unpaired bases that help the gene attach to new DNA).
Insertion into Plasmid – A bacterial plasmid (a small circular DNA molecule) is cut using the same restriction enzyme, creating complementary sticky ends.
DNA Ligase Joins DNA – Ligase enzyme joins the gene and the plasmid together to form recombinant DNA.
Insertion into Host Cell – The recombinant plasmid is inserted into a bacterial cell.
Replication & Expression – The modified bacteria multiply, producing the desired protein (e.g., insulin).
Screening & Selection – Successfully modified bacteria are identified and used.
225
How are antibiotic markers are used to select cells with the new DNA in genetic engineering
A marker gene ,which codes for antibiotic resistance, is inserted into the vector at the same time as the desired characteristics
The host bacteria are grown on a plate also only the bacteria that contain the marker gene are able to survive and reproduce the antibiotics will kill the rest
226
How is agrobacterium tumerfaciens used to genetically modify plants
agrobacterium tumerfaciens invades plant cells and inserts its genes into plants DNA
Once the agrobacterium tumerfaciens bacteria is genetically modified to include a useful gene like. pesticide resistance then bacteria will infect the target plant
the bacteria will insert their genes into the plants DNA
227
Benefits of genetic engineering
Resistance to illnesses
More nutritious food
Drought resistance
Faster growing plants and animals
228
Risks of genetic engineering
Affects food chains and human food intake
Don't know the long term effects
229
