Respiration occurs in the __________(1) providing energy for life proccess.
1. mitochondria
Chromosomes in the nucleus...
- Carry coded information in the form of genes
- Are made of a molecule called DNA.
Information in genes is in the form of
coded instructions called the ______________(1).
1. genetic code
The genetic code controls ____ ________(1) and consequently some characteristics of the organism.
1. cell activity
DNA controls the production of different
________(1).
1. protiens
The structure of DNA was first worked out
by two scientists called ________( 1) and _________(2).
1. James Watson
2. Francis Crick
Describe how Watson and Crick used data from other scientists to build a model of DNA
The data they used showed that bases occurred in pairs. Further x-ray data showed that there were two chains wound into a double helix.
Explain why liver and muscle cells have large numbers of mitochondria.
They require more energy
What are ribosomes?
Structures in the cytoplasm of a cell, where protiens are assembled
Some structures in cells, such as ribosomes, are
too small to be seen with the light microscope
...
Ribbosomes are in the cytoplasm and are the site
of protein synthesis
...
The structure of DNA has two strands coiled
to form a _________(1), each strand containing
chemicals called _____(2), of which there are four
different types.
1. Double Helix
2. bases
Chromosomes as long, coiled molecules of
DNA, divided up into regions called _____(1)
1. genes
Each gene...
- Contains a different sequence of bases
- Codes for a particular protein.
Why is a copy of a gene needed?
Becuse the gene itself cannot leave the nucleus
What are the four bases of DNA?
(Full names not required)
A T C and G
Describe the complementary base pairings
A always pairs with T
G always pairs with C
Explain how protein structure is determined by the
DNA base code?
- Proteins are made from lots of amino acids joined together in long chains. Each amino acid is coded by the sequence (order) of three bases (base triplets). For example, GGT codes are found in glycine
- The sequence of bases determines the sequence of am
The code needed to produce a protein is
carried from the DNA to the ribosomes by a molecule called ____(1).
1. mRNA
Name three examples of proteins
Collagen
Insulin
Haemoglobin
What are Enzymes?
Proteins that are used to speed up biologicaly reactions such as respiration. They work best at a paricular temperature.
What is a gene mutation?
A change in the gene
Describe some functions of proteins
Structural - Collagen
Hormones - Insulin
Carrier Molecules - Haemoglobin
Enzymes
Lock and key mechanism
(For enzymes)
Explain how enzyme activity is affected by pH and temperature
- Lower collision rates at low temperature
- Denaturing at extremes of pH and high temperatures
- Denaturing is an irreverisible change inhibiting enzyme function
- Denaturing changes the shape of the active cell
What is the formula for working out the Q10 (the temperture coefficient)?
Rate at higher temperature
-----------------------=Q10
Rate at lower temperature
Gene ma lead to the prodction of different _________(1).
1. proteins
Mutations occur spontaneously but can be made to occur more often by __________(1) or chemicals.
1. radiation
Mutations are often harmful but may be _________(1) or have no effect.
1. benefictual
Only some of the full set of genes are used in any one cell; some genes are ________ ___(1). The genes switched on determine the functions of a cell.
1. switched off
What is the word equation for aerobic respiration?
Glucose + Oxygen ---> Carbon Dioxide + Water + (Energy)
Describe examples of life processes that require
energy from respiration
Muscle contraction
Protein synthesis
Control of body temperature in mammals
What is the symbol equation for aerobic respiration?
What is the formula for calculaing the respiratory quotient (RQ)?
Carbon dioxide produced
---------------------- = RQ
Oxygen used
What is ATP?
Energy
What is the metabolic rate?
A of of how quickly all the chemical reactions are going on in the organisms body.
What is the rate of oxygen consumption?
The amont of oxygen an organism uses in a particular time period.
The rate of oxygen consumption can be used as an estimate of metabolic rate because...
aerobic respiration requires oxygen.
Explain why the rate of respiration is influenced by
changes in temperature.
Muscles warm up a bit during warm before exercise - respiration reactions go more quickly. When exercise begins respirations is faster and more energy is released.
Explain why the rate of respiration is influenced by
changes in pH.
The increased lactic acid from anaerobic respiration lowers the pH. This reduces enzyme activity, and so rate of respiration is reduced. Muscles get fatigued.
This is painful and your muscles stop contracting.
Explain why anaerobic respiration takes place during
hard exercise in addition to aerobic respiration.
During hard exercise, your heart rate doesn't go up quickly enough to supply the extra oxygen. To make up the shortfall in energy release, your muscle cells unaerobic respiration as well as aerobic respiration.
What is the word equation for anaerobic respiration?
Glucose ---> Lactic Acid + (Energy)
Explain fatigue in terms of lactic acid build up and how this is removed during recovery
During hard exercise your muscles become fatigued due to lack of oxygen. Anaerobic respiration breaks glucose incompletely and produces lactic acid. When you stop exercising - your heart rate stays high so the blood can quickly carry lactic acid to the li
What is oxygen debt?
Lack of oxygen in muscle cells. Oxygen is needed to oxidide the lactic acidin the muscle to carbon dioxide and water.
Describe the difference between unicellular and multicellular.
Unicellular - consist of one cell
Mulricellular - consist of many cell
Explain why the chromosomes have to be copied to
produce new cells for growth
So that each cell has a complete set of genetic material
What are gametes?
Another word for sex cells
Gametes have ________(1) the number of
chromosomes of body cells.
1. half
In sexual reproduction gametes join in
__________(1).
1. fertilisation
Explain why sperm cells are produced in large
numbers.
To increase the chances of fertilisation
Describe the adavntages of multicellular.
Allows organism to be larger
Allows for cell differentiation
Allows organism to be more complex
How are new cells produced?
Through the process of Mitosis
In mammals, body cells are...
diploid
What is a diploid?
Describes a cell that has a nucleus with two sets of chromosomes; a body cell
Explain why DNA replication must take place before
cells divide
So that each cell has a complete set of genetic materials.
Gametes are produced by...
Meiosis
Gametes (sex cells) are h_______...
Haploids
What is a haploid?
Describes a cell that has a nucleus with one set od chromosomes; a sex cell
Explain why fertilisation results in genetic variation
Gametes combine to form a diploid zygote
Genes on the chromosomes combine to control
the characteristics of the zygote.
Explain how the structure of a sperm cell is adapted
to its function
Many mitochondria to provide energy
An acrosome that releases enzymes to digest (break down) the egg membrane.
Explain why becoming multicellular requires the
development of specialised organ systems
Communication between cells- the nervous system
Supplying the cells with nutrients- the circulatory system
Controlling exchanges with the environment- the respiratory and digestive system
Explain how a DNA molecule replicates
Double Helix 'unzips' into two different strands; this exposes the DNA bases on each starnd
Spare DNA bases in the nucleusline up against each separated starnd of DNA.
The align against their complementary DNA base, forming new base pairs.
Explain how Mitosis occurs
The chromosomes:
line up along the centre of the cell
they then devide
the copies move to oppisite poles of the cell
Note: You don't have to rememeber the names of the steps in the picture provided
how Meiosis occurs
In Meiosis, the cells divide twice, forming four gametes
One chromosome from each pair separate to opposite poles of the cell in the first division
Chromosomes divide and the copies move to opposite poles of the cell in the second division.
What are the 4 main components of blood
Red Blood Cell
White Blood Cell
Platelets
Plasma
What is the function of the red blood cell?
Carries oxygen from lungs ti respiring tissues
What is the function sof the white blood cell?
Helps defend you against diseases by:
ingesting bacteria
making antibodies
What is the function of the platelets
Help your blood to clot when you cut yourself
What is the function of the plasma?
Plasma is the largest component of blood, It's mainly made of water and surrounds the blood cells, carrying them around the body. Plasma also helps maintain blood pressure and regulates body temperature.
Blood moves around the body in..
Arteries
Veins
Capillaries
Describe the functions of the heart in the pumping of
blood
The right side of the heart pumps blood to the
lungs
The left side of the heart pumps blood to the rest
of the body.
Blood in ________(1) is under higher pressure
than blood in the ______(2).
1. Arteries
2. Veins
Explain how red blood cells are adapted to its function in terms of it's size
They are small diameter and relatively thick. This means:
- They can fit through capillaries, one at a time.
- Surafce Area to Volume ratio so a lot of oxygen can diffuse through the outer surface and into the center of the cell.
Explain how red blood cells are adapted to its function in terms of it's shape
They are binocave discs (doughnuts shaped). This increases it's surface area/volume further.
Explain how red blood cells are adapted to its function in terms of the fact that it has no nucleus
Before each red blood cell leaves the bone marrow, where it is made, and enters the bloo, it's nucleus breaks down. This leaves more room for lots of haemoglobin.
Describe how oxyhaemoglobin is formed
In the lungs the haemoglobin in the red blood cells reacts with oxygen, forming oxyhaemoglobin
At respiring cells the oxyhaemoglobin breas down to haemoglobin and oxygen. The oxygen is delivered to the respiring cells .
Describe how the parts of the circulatory system work
together to bring about the transport of substances
around the body
The arteries transport blood away from the heart
The veins transport blood to the heart
The capillaries exchange materials with tissues
Labeled diagram of the heart
Note: You must remebr the labels
Describe the functions of the:
- left and right ventricles
- left and right atria
- semilunar, tricuspid and bicuspid valves
Left and right ventricles pump blood
Left and right atria recieve blood
Semilunar, tricuspid and bicuspid valves prevents backflow
Explain why the left ventricle has a thicker muscle
wall than the right ventricle.
The right ventricle pumps blood to the lungs only, whereas the left ventricle has to pump blood to the rest of the body. It has a thicker wall becuase it needs to generate a higher pressure to allow fast delivery of oxygen to the body tissues.
Explain how the adaptations of arteries relate to their functions
Arteries have a thick muscular and elastic wall - they can with stand the high pressure the pressure generated by the heart pumping blood into them
Explain how the adaptations of veins relate to their functions
Veins have a thinner wall and a larger lumen (space inside them) The blood is under low pressure. To prevent blood flowing backwards, the veins have valves
Explain how the adaptations of capillaries relate to their functions
Capillary walls are permeable (absorbent)
Explain the advantage of the double circulatory
system in mammals,
There is a higher pressure
Therefore a greater and faster flow to the tissues
Describe the functions of parts of a plant cell
Cell wall
Chloroplasts
Vacuole
Cell wall - made of cellulose to provide support
Chloroplasts - Contain chlorophyll, which absorbs light energy for photosynthesis
Vacuole - filled with cell sap to help keep the cell turgid
Bacterial cells are ________(1) and
simpler than plant and animal cells.
1. smaller
Growth can be measured as an increase
in...
Height
Dry mass
Wet mass
Describe the process of growth as cell division
followed by cells becoming specialized.
Through cell division, a single cell becomes two cells. Those two cells divide into four, and the four cells divide into eight, and so on. A multicellular organism grows because cell division increases the number of cells in it. As the organism develops a
The process of cells becoming specialised
is called ___________.
Differentiation
Animals grow in the early stages of
their lives whereas plants grow __________(1).
Continually
All parts of an animal are involved in growth whereas plants grow at S______ p____ (1) of the plant.
Specific Parts
Identify simple differences between bacterial cells
and plant and animal cells.
Bacterial cells lack:
- a 'true' nucleus
- mitochondria
- chloroplasts.
D__ M____ is the best measure of growth.
Dry Mass
In human growth there are two phases of rapid growth, one just after b____(1) and the other in a____________(2).
1. Birth
2. Adolescence
Undifferentiated cells called s___ c_____(1) can
develop into different cells, tissues and organs.
1. Stem cells
Stem cells can be obtained from e________ t_____(1) and could potentially be used to treat medical conditions.
1. Embryonic tissue
What are the issues arising from stem cell research in
animals.
Unethical
Against religion beliefs
Explain why plant growth differs from animal growth
- Animals tend to grow to a finite size but many plants can grow continuously
- Plant cell division is mainly restricted to areas called meristems
- Cell enlargement is the main method by which plants gain height
- Many plant cells retain the ability to d
The difference between the arrangement
of DNA in a bacterial cell and a plant/animal cell
Instead of a cell nucleus containing chromosomes, the DNA in bacterial cells is arranged in a single circular strand in the cytoplasm.
Describe the advantages and disadvantages of
measuring growth by:
Length
Advantages:
Easy, quick and no need to kill the organism
Disadvantages:
Lack of accuracy
Describe the advantages and disadvantages of
measuring growth by:
Dry Mass
Advantages:
Accurate
Disadvantages:
The organism will be killed.
Time consuming.
Describe the advantages and disadvantages of
measuring growth by:
Wet Mass
Advantages:
Easy to measure and no need to kill the organism.
Disadvantages:
Less accurate and changes in the water content of an organism are not related to growth
Explain the difference between adult and embryonic
stem cells.
One major difference between adult and embryonic stem cells is their different abilities in the number and type of differentiated cell types they can become.
Decribe the process of natural breeding
A desired characteristic is decided
An organism that show these characteristics are cross bred
The best offspring is selected from parents to breed the next generation
Explain how selective breeding can contribute to improved agricultural yields.
Example:
Increasing milk yield by selecting bulls from high yield herds and breeding them with cows that have the best milk production.
Selected genes can be _______(1) transferred from one living organism to another
This transfer of genes is called g________ e________(2) or genetic modification
The transfer of genes can produce organisms with
different characteristics.
1. Artificially
2. Genetic Engineering
A selective breeding programme may
lead to i_________(1), which can cause health problems
within the species.
1. Interbreeding
Explain some potential advantages and risks of
genetic engineering
Advantage - organisms with desired features are
produced rapidly
Risks - inserted genes may have unexpected
harmful effects.
Describe, in outline only, some examples of genetic
engineering:
- The production of human insulin by genetically
engineered bacteria
- Transferring resistance to herbicides, frost
damage or disease to crop plants
The changing a person's genes in an attempt
to cure disorders is called
Gene Therapy
What is a gene pool?
The stock of different genes in an interbreeding population.
In the selective breeding process, interbreeding may reduce the gene pool, This could lead to...
- an accumalation of harmful recessive characteristics leading to health problems
- reduction of variation
What are the principals of genetic engineering?
Selection of desired characteristics
Isolation of genes responsible
Insertion of the genes into other organisms
repilcation of these organisms
Gene therapy could involve b___ c___(1) or
g______(2).
1. Body cells
2. Gametes
Explain why gene therapy involving gametes is
controversial
because it is sometimes difficult to decide what genes parents should be allowed to change.
It could lead to designer babies
True or False. Cloning is an example of asexual reproduction
True
True or False. Cloning produces genetically identical copies
True
Dolly the sheep was the first m_______(1) cloned from an adult.
1. mammal
True or False. Plants grown from cuttings or tissue
culture are clones.
True
Dolly the sheep was produced by the
process of n______ t______.
Nuclear transfer
What is nuclear transfer?
Involves placing the nucleus of a body cell into an
egg cell
Describe some possible uses of cloning.
- Mass producing animals with desirable
characteristics
- Producing animals that have been genetically
engineered to provide human products
- Producing human embryos to supply stem cells
for therapy
Describe the advantages associated with the commercial use of cloned plants
- Can be sure of the characteristics
of the plant since all plants will be genetically
identical
- It is possible to mass produce plants
that may be difficult to grow from seed
Describe the disadvantages associated with the commercial use of cloned plants
- If plants become susceptible to
disease or to change in environmental conditions
then all plants will be affected
- Lack of genetic variati
Describe in outline the cloning technique used to
produce Dolly the sheep
- Nucleus removed from an egg cell
- egg cell nucleus replaced with the nucleus from
an udder cell
- egg cell given an electric shock to make it divide
- embryo implanted into a surrogate mother sheep
- embryo grows into a clone of the sheep from
which th
Describe the benefits of using cloning technology.
Creation of replacement organs and tissues
Could allow infertile parents to have children
Extednign life by replacing ageing tissues and organs
Describe the risks of using cloning technology.
Humans created as toolsor products for medicine
Clones would be identical twins of the cell donor
Research to prefect cloning could lead to damaged clones
Decreasing genetic diversity casued by asexaul cloning
Describe plant cloning by tissue culture
- selection for characteristics
- large number of small pieces of tissue
- aseptic technique
- use of suitable growth medium and conditions.
Explain why cloning plants is easier than cloning
animals
Many plant cells retain ability to differentiate
unlike animal cells which usually lose this ability at an
early stage