Biology 2 Flashcards
What three types of tissues do humans have?
Muscular tissue- Contracts in order to move what it attached to
Glandular tissue- It releases hormones and substances
Epithelial tissue- Covers part of the body
What three tissues do plants have?
Epidermal- Covers the surface of the plant
Mesophyll- Where photosynthesis occurs
Xylem and phloem- Allows things to be transported around the plant
What three organs do plants have?
Leaves
Stem
Roots
What is the word equation for photosynthesis?
Carbon dioxide + Water (with light energy) Glucose + Oxygen
How does light intensity effect the rate of photosynthesis?
As light intensity is increased, the rate of photosynthesis increases as well but only up to a certain point as carbon dioxide or the temperature will become the limiting factor.
How does carbon dioxide concentration effect the rate of photosynthesis?
The amount of carbon dioxide will increase the rate of photosynthesis up to a point and then either the temperature or the light intensity will become a limiting factor.
How does temperature effect the rate of photosynthesis?
If the temperature is the limiting factor it may be because it is too low and therefore the enzymes work slowly. If the temperature is too high it can also effect the rate of photosynthesis as the enzymes will denature.
How does a greenhouse control temperature?
They trap the sun’s heat and prevent the temperature for, becoming the limiting factor.
How does a greenhouse effect the light intensity?
So photosynthesis can occur during the night, people can apply artificial lighting.
How does a greenhouse effect the carbon dioxide concentration?
Paraffin heaters are used which burn and produce carbon dioxide as a by-product.
What is glucose used for in plants?
Respiration
Making cell walls- Glucose is converted into cellulose
Making proteins- Glucose is used to make amino acids and glucose is combined with nitrate ions to make amino acids which are them made into proteins
How is glucose stored?
Lipids
Starch- It is insoluble where as glucose is not so it would swell as it absorbs water
What is a habitat?
A place where an organism lives
What is distribution?
The location of an organism
What factors affect the distribution of organisms?
Temperature Availability of water Availability of nutrients Availability of oxygen Availability of carbon dioxide Amount of light
What does reproducibility mean?
Study can be repeated and the same results will be collected.
What does validity mean?
Results are repeatable and reproducible.
What are the functions of proteins?
Catalyst
Antibodies
Hormones
Structural component of tissue
What gives an enzyme its unique shape?
The folding of long chains of amino acids which are held together by bonds.
Optimum conditions for enzymes- Temperature
A high temperature will increase the rate of reaction to begin with but if it gets too warm the bonds holding the enzyme together break. They become denatured and the shape is destroyed.
Optimum conditions for enzymes- pH
If the pH is too low or too high the pH interferes with the bonds. This alters the shape and destroys the enzyme.
What is mechanical digestion?
When our teeth grind down food and our stomach churns up food.
What is chemical digestion?
Enzymes help to break down food.
Why does the stomach produce hydrochloric acid?
Kills bacteria and give the correct pH for protease enzymes to work.
What is bile?
Produced in the liver.
Bile is an alkali so it neutralises the hydrochloric acid in the stomach as enzymes in the stomach work best in alkaline conditions.
Bile breaks fat into smaller droplets which provides a larger surface area for lipase to work which allows digestion to occur more quickly.
Enzymes in baby food
Baby foods have been pre-digested by proteases so the food is easier to digest.
Mitochondria
Where respiration takes place
Ribosomes
Where proteins are made
Yeast cell (single-celled microorganism)
Nucleus
Cytoplasm
Cell membrane
Cell wall
Bacterial cells (single-celled microorganisms)
Cell wall
Cell membrane
Cytoplasm
Genetic material
What is a specialised cell?
A cell which is able to perform a specific function
What is diffusion?
The spreading out of particles from an area of high concentration to an area of low concentration
What is a tissue?
Group of similar cells which work together in order to carry out a specific function.
What is an organ?
Group of different tissues which work together to perform a certain function.
What is an organ system?
Group of organs which work together in order to perform a particular function.
How do cells become specialised?
They differentiate.
What is used to artificially control plants?
A green house.
What does the enzyme amylase break down?
It breaks down starch into sugars.
What does the enzyme proteases break down?
They break down proteins into amino acids.
What does the enzyme lipase break down?
It breaks down lipids into glycerol and fatty acids.
Where is amylase made and where does it work?
It is made in the 1)Salivary glands 2)Pancreas 3)Small intestine It works in the 1)Mouth 2)Small intestine
Where is protease made and where does it work?
It is made in the 1)Stomach 2)Pancreas 3)Small intestine It works in the 1)Stomach 2)Small intestine
Where does lipase work and where is it made?
It is made in the 1)Pancreas 2)Small intestine It works in the 1)Small intestine
What are the advantages of using enzymes in the industry?
Biodegradable
Can be re-used
Can be used at low temperatures and pressures
They are specific so they only catalyse the reactions you wish them to
What is respiration?
The process which releases energy from glucose
What is the word equation for aerobic respiration?
Glucose + Oxygen (goes to) Carbon dioxide + Water + Energy
How do you use energy released by respiration?
Maintain a constant body temperature
Needed for muscles to contract
Build amino acids from from sugars and nitrates which are then built into proteins
Smaller molecules are built up into larger molecules
What happens to glycogen during exercise?
It is converted into glucose so respiration can occur and then more energy will be released.
What is the word equation for anaerobic respiration?
Glucose (goes to) Energy + Lactic acid
Anaerobic doesn’t release as much energy as the glucose is not completely broken down.
What does lactic acid cause?
Muscle fatigue. Blood flowing through muscles removes the lactic acid.
What is oxygen debt?
It is when the muscles did not get enough oxygen during exercise and therefore afterwards it needs to be repaid with the oxygen it did not get. In order to repay the oxygen you have to breath for a while after exercise to get oxygen into your blood. As the blood flows through the muscles the lactic acid is removed as it is oxidised to carbon dioxide and water.
What is a gene?
Section of DNA
What is mitosis and what are the uses?
A cell can produce identical cells by splitting. Uses: Used for growth Used to replace cells Used in asexual reproduction
What are the stages of mitosis?
1) The DNA is copied in order to form x shaped chromosomes.
2) The chromosomes line up in the centre and cell fibres pull them apart.
3) Around the new sets of chromosomes a membrane forms.
4) The cytoplasm divides forming identical cells.
What is meiosis?
Cells which contain half the number of chromosomes and it occurs in reproductive organs in humans.
What are the stages involved in meiosis?
1) A cell duplicates its DNA
2) The chromosomes line up in the centre of the cell and they are pulled apart so each cell has a copy of each chromosome.
3) A second division occurs as the chromosomes line up in the centre and the arms are pulled apart.
What did Mendel conclude?
Hereditary units can be either dominant or recessive.
They are passed on from both
They determine characteristics
What does the word homozygous and heterozygous mean?
Homozygous-
Two alleles which are the same
Heterozygous-
Two alleles which are different
What are genetic disorders?
Caused by an abnormal gene or chromosome.
What is cystic fibrosis?
It causes the body to produce mucus in the air passages and the pancreas.
It is caused by the recessive allele so you can be a carrier.
What is polydactyly?
When someone has extra fingers or toes.
Cause by the dominant allele.
Why is embryonic screening used?
It can detect a genetic disorder.
What is pre-implantation genetic diagnosis?
Occurs during IVF when the embryos have a cell removed to check its genes. Certain embryos will then be implanted whilst others will be destroyed.
What is chorionic villus sampling?
Occurs during ten to thirteen weeks of pregnancy. Cells are taken from part of the placenta and their genes are analysed. If a genetic disorder is found then it gives the option to end the pregnancy.
What are the four advantages of embryonic screening?
Decreases health care costs.
Stops people suffering.
Chorionic villus sampling gives the choice to end the pregnancy.
Pre-implantation genetic diagnosis ensures that the embryo is healthy.
What are the four disadvantages of embryonic screening?
Embryos get destroyed (with PGD).
CVS could result in the ending of a pregnancy.
Everyone may want to do it at some point.
It creates ideas that those with genetic disorders are undesirable.
What are fossils?
Remains of organisms which are located in rocks.
Name the three ways fossils form.
Casts and impressions.
Preservation.
Replacement by minerals.
Explain how fossils form by gradual replacement with minerals.
As things such as bones decay, they are replaced by minerals.
Explain how fossils form from casts and impressions.
When organisms are buried in a soft material such as clay, it hardens as the organism decays which leaves a cast.
Explain how fossils are formed from preservation where decay does not occur.
If the conditions aren’t correct then decay cannot happen and the remains will be preserved. The conditions needed for decay are oxygen, moisture, the correct pH and the correct temperature so that the enzymes are able to work.
Why is there a lack of evidence about how life on Earth began?
Many of the early organisms were soft bodied so they would decay without leaving fossils.
Also, geological activity such as earthquakes may have destroyed fossils.
What is meant by the word extinction?
When an organism no longer exists.
Why do species become extinct?
A disease. A geological event. A predator. Competition. Speciation. Environment changes rapidly.
What is speciation?
Development of a new species.
What is a specie?
Group of similar organisms that can reproduce to give fertile offspring.
What is meant by the term isolation?
Where a specie is separated.
True or false.
Speciation leads to isolation.
False.
Isolation leads to speciation.
Describe the process of natural selection, including both isolation and speciation.
1) A specie becomes isolated as a result of a physical barrier.
2) The conditions on either side of the barrier will differ.
3) There will be variation in the populations due to a range of alleles.
4) The organisms with the more beneficial characteristics are likely to survive and reproduce.
5) The beneficial alleles for the specific environment will be passed on to the next generation.
6) Over time the organisms from the two environments would have changed so much that they won’t be able to breed to produce fertile offspring.
