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- Created by: ilke1211
- Created on: 23-04-17 13:03
What are mitrochondria ?
Mitochondria is the powerhouse of the cell. It is where respiration takes place within a cell. They are found in the cytoplasm and the number of them depend on the activity of the cell. They provide energy for life processes
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Why does the liver and muscles contain many mitochondria ?
This is because the livercarries out many functions and the muscles need to contract , which both take alot of energy.
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What are ribosomes ?
Ribosomes are smaller than mitochondria and are also found in the cytoplasm. They are the site of protein synthesis and are too small to be seen by a light microscope.
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What are chromosomes and what do they do ?
A chromosome is a long coiled molecules of DNA that carries coded information in the form of genes.
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What does a gene do ?
It contains a different sequence of bases and codes for a particular protein
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What is the name for information in genes in the form of coded instructions ?
Genetic code
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What does the genetic code control ?
Cell activity and consequently some characteristics of the organism.
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What does DNA control ?
The production of different proteins
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What are proteins needed for ?
Growth and repair of the cell
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What is the double helix structure ?
It is two strands of DNA coiled together with each strand containing chemicals called bases with cross links between the strands formed by pairs of bases
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Who found the double helix structure ?
Watson and Crick
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What are the four bases ?
A,T,C,G
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Which bases link together ?
A-T C-G
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Why is a copy of gene needed ?
The gene itself cannot eave the nucleus, so a copy needs to be made so that it can leave the nucleus and carry the code to the cytoplasm
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Where are protens made ?
In the cytoplasm
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How is protein structure determined by the DNA base code ?
The DNA base sequence determines the amino acid sequence in protein. Each amino acid is coded for by a sequence of 3 bases.
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How is the code that is needed to make a protein carried from the DNA to the ribosomes ?
Through a molecule called messenger RNA, or mRNA
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How does DNA control cell functions ?
It does this by controlling the production of proteins, some of which are enzymes
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How did Watson and Crick design the double helix model using data from other scientists ?
They used photographs which were taken using x-rays which showed that DNA had two chains wound into a helix, and also they used data indicating the bases occured in pairs
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Why did Watson and Crick have to wait for so long until they were awarded for their discovery ?
This is because for new discoveries other scientists must be able to repeat the work to check the discovery to make sure that it is correct.
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What are some examples of proteins ?
Haemoglobin, collagen, insulin
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What are enzymes ?
Proteins that speed up a biological/chemical reaction (catalyst) and work best at a particular temperature
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What happens when reactions take place with enzymes present ?
An enzyme has has an ACTIVE SITE in which a SUBSTRATE molecule fits into. This is why an enzyme working is decribed as a lock and key mechanism
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Different cells and different organisms will produce
different proteins
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What is gene mutation ?
Changes to genes
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What are proteins made of ?
Long chains of amino acids
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What are some functions of proteins ?
Structural, proteins used to build cells and tissues, e.g collagen. Hormones, which carry messages to control a reaction, e.g insulin controls blood sugar levels. Carrier proteins, e.g haemoglobin, which carries oxygen. Enzymes
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Each protein has ...
Its own number and sequence of amino acids which results in different shaped molecules, which have different functions.
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Each enzyme has a high specificity for ...
their substrate
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How is enzyme ativity affected by pH and temperature ?
At low temps molecules are moving more slowly so the enzyme and substrate will less likely collide. At high temps the enzyme denatures so the substrate cannot fit, so cannot react so quickly.
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What formula can you use to work out how temperature alters the rate of the reaction ?
By calculating the temperature coefficent called Q10. This is done at a 10°C. Q10= rate at higher temp / rate at a lower temp
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What may gene mutation lead to ?
The production of different proteins
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Do mutations have to be triggered by something to be made ?
No, mutations occur spontaneously but can be made to occur more often by radiation and chemicals
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Do mutations always kill the organism ?
No, they are often harmful but may have no effect and in same cases mnay be beneficial to the individual as it gives them and advantage.
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Do all cells make the same protein ?
No, although they all have the same genes it does not mean all the same proteins are made. This is because genes are switched off in different cells. This allows different cells to perform different functions.
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The genes switched on ...
perform diiferent functions
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How to changes to genes alter/prevent the production of proteins which are normally made ?
Gene mutations alter or prevent the production of the protein that is normally made, because they change the base code of DNA , and so change the order of amino acds in the protein
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Energy provided by respiration is ...
needed for all life processes in plants and animals
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What is the word equation for aerobic respiration ?
Glucose + Oxygen → Carbon Dioxide + Water
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What are examples of life processes that require energy from respiration ?
Muscle contraction, Protein synthesis, Control of body temperature in animals
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Why does breathing and heart rate increase during exercise ?
This is because your heart is pumping more oxygen and food to the muscles which increases heart rate and more oxygen is inhaled so that carbon dioxide is removed and more oxygen can be sent to muscles.
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How do you measure your pulse rate ?
Count how many heart beats you have in a particular time period and multiply it by a number to get to 60 e.g 25 beats in 15 seconds mean your resting heart rate is 100 bpm as 15x4=60 so 25x4=100
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What is the symbol equation for aerobic respiration ?
C^6 H^12 O^6 + 6O^2 → 6CO^2 + 6H^2 O
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How do you calculate the respiratory quotient (RQ) ?
RQ = Carbon dioxide produced / oxygen used
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What does respiration produce ?
A molecule called ATP
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What is ATP used as ?
The energy source for many processes in the cells
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How can rate of oxygen consumption can be used as an estimate for the metabolic rate ?
The rate of oxygen consumption can be used as an estimate of metabolic rate because aerobic respiration requires oxygen.
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Why is the rate of respiration is influenced by changes in temperature and pH.
This is because they affect enzymes and respiration that is controlled by enzymes
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Why does anaerobic respiration take place along with aerobic during hard exercise ?
This is because often the muscles do not recieve sufficent oxygen, so also use anaerobic respiration as an energy source.
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What is the word equation for anaerobic respiration ?
Glucose → lactic acid (+ energy)
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What are two main disadvantages of anaerobic respiration compared to aerobic respiration ?
Lactic acid is created as a result of anaerobic respiration which can cause pain and fatigue. Also anaerobic respiration releases much less energy per glucose molecule than aerobic respiration.
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What does the incoplete breakdown of glucose result in ?
The build-up of lactic acid (oxygen debt)
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Why does the heart and breathing rate stay high during recovery ?
So that therethe rapid blood flow can carry lactic acid away to the liver, and extra oxygen can be supplied enabling the liver to break down lactic acid.
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What is a unicellular organism ?
An organism made from one cell , that are very simple and small. e.g bacteria
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What is a multicellular organism and its advantages ?
An organism made up of many cells, that are much larger and complex. It allows different cells to takeon different jobs. This is called cell differentation
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Most body cells contain chromosomes in ...
matching pairs
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What is the process that produces new cells for growth is called ?
Mitosis
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Chromosomes have to be copied to produce new cells for growth because ...
the cells made by mitosis are identical. Before cells divide DNA replication must take place. This is so that each cell produced still has two copies of each chromosome.
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What is mitosis also needed for ?
Replacement of worn out cells, Repair to damaged tissue, Asexual reproduction
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What is a gamete ?
A sex cell ( sperm or egg cell )
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In what stage of sexual reproduction do the gametes join ?
Fertilization
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What is a haploid cell ?
A cell that only contains one set of chromosomes e.g sperm cell and egg cell
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What is a diploid cell ?
A cell that contains two sets of chromosomes e.g body cells
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In sexual reproduction to produce a unique individual ...
half the genes come from each parent
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Why are sperm cells produces in large numbers ?
To increase the chance of fertilization
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What is the type of cell divison that produces gametes ?
Meiosis
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Why do multicellular organisms require specialised systems ?
So that it can allow communication between all the cells in the body, supply all the cells with enough nutrients, and control exchanges with the enviroment such as heat and gases.
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How does DNA replication occur prior to mitosis ?
The DNA 'unzips' to form single strands, then new double strands form by DNA bases lining up in complementary pairings.
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In mitosis ...
The chromosomes line up along the center of the cell and divide. The copies move to opposite poles of the cell
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Why does fertilization result in genetic variation ?
Gametes combine to form a diploid zygote (two haploid cells fused), genes on the chromosome combine to control the characteristics of the zygote
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How is a sperm cell adapted to its purpose ?
It has many mitochondria to provide energy and an ACROSOME that releases enzymes to digest the egg membrane.
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In meiosis why is the chromosome number halved and each cell genetically different ?
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.
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What is the function of a red blood cell ?
To carry oxygen around the body
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What is the function of a white blood cell ?
To protect the body from foreign invaders and infectious diseases
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What is the function of platelets ?
To prevent bleeding
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What are the name of blood vessels ?
Arteries, Veins, and Capillaries
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What is the function of the heart ?
To pump oxygenated blood around the body. The right side pumps the blood to the lungs to recieve oxygen whereas the left side pumps the blood to the rest of the body
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Which has higher blood pressure: the artery or the vein , and why ?
The artery because of the heart pumping blood through it to reach all around the body
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Explain, in terms of pressure difference, why blood flows from one area to another.
Blood flows from areas of high pressure to low pressure
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How are red blood cells adapted to its function ?
They are small so can pass through capillaries, They are shaped like biconcave discs so have a large surface area to exchange oxygen quicker, They contain haemoglobin to combine with oxygen, They dont have a nucleus so can fit more haemoglobin.
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What is plasma and what is its function ?
The plasma is the liquid part of the blood and carry important substances such as: Disolved food substances e.g glucose, C02 from tissues to the lungs, hormones from the glands where they are made, to their target, Plasma proteins e.g antibodies
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How does haemoglobin in the red blood cells with oxygen in the lungs ?
It forms oxyhaemoglobin which is a reversible reaction: when the oxygen reaches the tissue, the oxygen is released.
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How do parts of the circulatory system work together to bring about the transport of substances around the body ?
Arteries transporting blood away from the heart, Veins transporting blood to the heart, Capillaries exchanging materials with tissue
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How do the adaptations of arteries, veins and capillaries relate to their functions ?
There are thick muscular and elastic wall in arteries, Large lumen and presence of valves in veins, Permeability of capillaries
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What are the names and positions of the parts of the heart and describe their functions ?
Left and right ventricles to pump blood, Left and right atria to receive blood, Semilunar; Tricuspid; and Bicuspid valves to prevent backflow, (the four main blood vessels of the heart) Vena Cava, Pulmonary artery, Aorta and Pulmonary Vein
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Why does the left ventricle has a thicker muscle wall than the right ventricle ?
This is because the left ventricle has to pump blood to the whole body rather than just to the lungs which are close by.
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What is the advantage of the double circulatory system in mammals ?
The blood is at a higher pressure and so flows to the tissues at a faster rate.
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What is the function of the vacuole ?
Contains cell sap and provides support
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What is the function of the cell wall ?
Made of cellulose and to provide support.
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How do you make a stained slide of an onion cell ?
1) Cut open an onion, 2) Use forceps to peel a thin layer of epidermis from the inside, 3) Lay the layer of epidermis on a microscope slide, 4) Add a drop of iodine solution to the layer, 5) Carefully place a cover slip over the layer
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How are bacterial cells different from plant and animal cells ?
Bacterial cells are smaller and lack a "true" nucleus, mitochondria and chloroplasts
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What can growth be measured as ?
An increase in height, dry mass and wet mass
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What is the process of growth described as ?
Cell division followed by cells becoming specialised
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What is the process of cells becoming specialised called ?
Differentiation
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What is the difference between animal and plant growth ?
Animals grow in the early stages of their life and all parts of their body grows whereas plants grow continually and only some parts of them grow
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What is the difference between the arrangement of DNA in a bacterial cell and a plant/animal cell ?
As bacterial cells do not have a true nucleus, DNA is found in the cytoplasm as a singular circular strand or chromosome
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What is the best way to measure growth ?
Measuring dry mass
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In human growth where are the two stages of rapid growth ?
Just after birth and after adolesence
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What are advantages of measuring growth by length ?
It is easy to do
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What are disadvantages of measuring growth by length ?
It only measures growth in one direction.
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What are advantages of measuring growth by wet mass ?
It is easy to measure for animals
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What are disadvantages of measuring growth by wet mass ?
It is hard to measure for plants and the water content of organisms can vary with time
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What are advantages of measuring growth by dry mass ?
It measures true growth of the whole organism
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What are disadvantages of measuring growth by dry mass ?
It can only be measured by killing the organism and driving off the water
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Why might different parts of an organism grow at different rates from the whole organism ?
This is because different parts of the organism may be needed at different times during the life of the organism
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What are undifferentiated cells are called ?
Stem cells and they can develop into different cells, tissues and organs
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What can stem cells be obtained from ?
Embryonic tissue (unborn babies) , and they can be potentially used to treat medical conditions
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What issues arrive from stem cell research in animals ?
Some people think that it is wrong because the embryos are being destroyed. Others think it is acceptable as it can treat life threatining diseases
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What is the difference between adult and embryonic stem cells ?
Embroynic stem cells form a greater range of cell types and are easier to find
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Why does plant growth differ 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, ell enlargement is the main method by which plants gain height,
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What is selective breeding ?
It is the process used by humans to create organisms with desired characteristics and is produced by cross-breeding organisms and keeping the most desired offspring.
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How selective breeding can contribute to improved agricultural yields ?
An example is cross-breeding wheat plants with disease resistance with wheat with high yield to produce wheat that has high yield and is resistant to diseases
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Describe genetice engineering
Selected genes can be artificially transferred from one living organism to another, this transfer of genes is called genetic engineering or genetic modification, the transfer of genes can produce organisms with different characteristics.
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What is a possibilty that may happen in the future due to genetic engineering ?
It may be used to change a persons genes and cure certain disorders such as cystic fybrosis
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What may selective breeding lead to ?
Inbreeding , which can cause health problems for the species
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Explain how a selective breeding programme may reduce the gene pool leading to problems of inbreeding
Accumulation of harmful recessive characteristics, reduction of variation
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Advantages of genetic engineering
Organisms with desired features are produced rapidly
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Disadvantages of genetic engineering
Inserted genes may have unexpected harmful effects
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Give an example of genetic engineering
The production of human insulin by genetically engineered bacteria
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Ethical issues involved with genetic modification
Some people are worried about possible long-term effectse.g genetically engineered plants or animals will disturb natural ecosystems
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What are the four steps of genetic engineering ?
1) Selection of desired characteristics 2) Isolation of genes responsible 3) Insertion of the genes into other organisms 4) Replication of these organisms
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Changing a person’s genes in an attempt to cure disorders is called ...
Gene therapy
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What could gene therapy involve ?
Body cells and gametes
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Why is gene therapy involving gametes is controversial ?
This is beacuse choosing what gametes parents are allowed to change is difficult as it could lead to designer babies
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What is cloning ?
Cloning is an example of asexual reproduction, Cloning produces genetically identical copies
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What was the name and species of the first mammal cloned from an adult ?
Dolly the sheep
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Identical twins are ...
a form of naturally occuring clones
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Plants grown from cuttings or tissue culture are ...
clones
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How do spider plants, reproduce asexually ?
Spider plants grow new plants, called plantlets, on their stems
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How do you take a cutting ?
1) Cut off a branch from the parent plant 2) Remove the lower leaves and plant the stem in damp compost 3) Plant hormones in rooting powder can be used to encourage new roots to develop 4) Cover the cutting in a clear plastic bag to keep it moist
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What was Dolly the sheep produced by ?
The process of nuclear transfer
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What is nuclear transfer ?
It involves placing the nucleus of a body cell into an egg cell
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What are some uses of cloning ?
The mass producing animals with desirable characteristics
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What are some uses of cloning ?
The mass production of animals with desirable characteristics, Producing animals that have been genetically engineered to provide human products, Producing human embryos to supply stem cells for therapy
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What are ethical dilemmas concerning human cloning ?
Some people think it is wrong to clone people as they will not be true individuals
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What is a more detailed version of Dolly the sheep's creation ?
1) Nucleus removed from egg cell 2) Egg cell nucleus replaced with the nucleus from an udder cell 3) Egg cell given an electric shock to make it divide 4) Embryo implanted into a surrogate mother sheep 5) Embryo becomes clone of udder cell sheep
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What are benefits and risks of using cloning technology for human organ replication ?
Genetically modified animals could be cloned to supply replacement organs for humans. However, some are worried that it could lead to diseases being spread from animals to humans
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What are 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, Also it is possible to mass produce plants that may be difficult to grow from seed
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What are 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. As well as this, there is a lack of genetic variation
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Describe plant cloning by tissue culture
1) A plant is selected for characteristics 2) Large number of small tissue pieces are then cut from plant 3) Small pieces then grown in test tube with growth medium 4) Aseptic technique is used at all stages to stop any microbes infecting plants
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Why is cloning plants easier than cloning animals ?
This is because plant cells retain the ability to differentiate, animal cells however, usually lose this ability at an early stage
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Other cards in this set
Card 2
Front
Why does the liver and muscles contain many mitochondria ?
Back
This is because the livercarries out many functions and the muscles need to contract , which both take alot of energy.
Card 3
Front
What are ribosomes ?
Back
Card 4
Front
What are chromosomes and what do they do ?
Back
Card 5
Front
What does a gene do ?
Back
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