biology unit 2

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what five parts of a cell do both animals and plants have
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes,
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what 2 parts do plant cells have that animals dont?
chloroplasts, cell wall, permanent vacuole
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what does the nucleus do?
contains genetic material that controls the activities of the cell
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what does the cytoplasm do?
The cytoplasm- A gell like subtance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions.
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What does the cell membrane?
Holds the cell together and controls what goes in and out.
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What does the mitochondria do?
These are where most of the reactions for respiration take place. Respiration releases energy that cell needs to work.
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What do the ribosomes do?
The ribosomes are where proteins are made in the cell.
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What does the cell wall do?
made of celluse. It supports the cell and strengthens it.
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what does the permanent vacuole do?
Contains cell sap a weak solution of sugar and salt.
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What does the chloroplast do?
These are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll.
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describe what a yeast cell has.
yeast is single celled organism: nucleus, cytoplasm, cell membrane, cell wall
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what does a bacteria cell have?
genetic material floating in cell, cytoplasm, cell membrane, cell wall.
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what is diffusion?
diffusion is the spreading out of particles from an area of high concentration to an area of low concentration.
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Name 2 substances that can diffuse through a cell membrane and two that can not.
amino acids and glucose can. Protein and starch cant.
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Give 3 ways that a palisade leaf cell is adapted to photosynthesis.
1) chloroplasts packed at the top of the cell so they're nearer the light. 2) tall shape means a lot of surface area exposed for absorbing co2. 3) Thin shape means that you can pack more of them on the top of the a leaf (where photosynthesises hap..
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give 3 ways that a sperm is adapted for swimming to an egg cell.
1) long tail 2) streamlined head to help it swim to the egg. 3) Alot of mitochondria in the cell to provide the energy needed.
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what is a tissue? what is an organ?
a tissue is a group of similar cells that work together to carry out a particular function. An organ is a group of different tissues that work together to perform a certain function.
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Give 3 examples of tissues in the human stomach, and say what job they do.
1) muscular tissue moves the stomach wall to churn up the food. 2) Glandular tissue, which makes digestive juices to digest food. 3) Epithelial tissue, which covers the outside and inside of the stomach.
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Name one organ system found in the human body
the digestive system.
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Give one example of a plant tissue and a plant organ.
tissue = mesophyll tissue organ= stems
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write down the equation for photosynthesis.
carbon dioxide + water ----- glucose + oxygen
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what is the green substance in leaves that absorbs sunlight?
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Name the three factors that can limit the rate of photosynthesis.
1) light intensity 2) temperature 3) co2
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You can carry out an experiment where you change the light intensity experienced by a piece of Canadian pondweed by changing the distance between the pondweed and a lamp supplying it with light. What three important things that must be kept constant?
tempreture, light intensiy and co2
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Explain why it is important that a plant doesn't get too hot.
if it gets too hot, the enzymes it needs for photosynthesis and its other reactions will be damaged.
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Describe three things that a gardener could do to make sure she grows a good crop of tomatoes in her greenhouse.
1) using artificial light 2) using a paraffin heater 3) adding fertiliser.
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why is glucose turned into starch when plants need to store it for later?
Starch is insoluble which makes it much better for storing than glucose ( A cell with lots of glucose in would draw in loads of water and swell up)
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write down four other ways that plants can use the glucose produced by photosynthesis.
For respiration, For making cell walls, making proteins
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What is a habitat?
A habitat is the place where an organisms lives.
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Give five environment factors that can affect the distribution of organisms.
1) temperature 2) availability of water 3) availability of oxygen and co2 4) Availability of nutrients. 5) amount of light.
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briefly describe how you could find out how common an organism is in two sample areas using quadrats
place quadrat on the ground at a random point within the first sample area. Count all the organisms within the quadrat. Repeat steps 1 and 2 as many times as possible. Work out the mean number of organisms per quadrat within the first sample area.
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how do you work out the mean with quadrats.
total number of organisms/ number of quadrats
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Describe one way of using a transect to find out how an organism is distributed across an area.
Mark out a line in the area you want to study using a tape measure. Then collect data along the line. You can do this by just counting all the organisms you're interested in that touch the line. Or you can collect data by using quadrats.
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give the definition of a catalyst
A catalyst is a substance which increases the speed of a reaction, without being changed or used up in the reaction.
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in which 3 places in the body is amylase produced?
1) the small intestines 2) the pancreas 3) the salivary gland
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where in the body is bile produced? stored? used?
produced= liver stored= gall bladder used= small intestines
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Explain why an enzyme- catalysed reaction stops when the reaction mixture is heated above a certain temperature.
some of the bonds holding the enzyme together break. This destroys the special shape and so it wont work any more. It is said to be denatured.
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Explain why the stomach produces hydrochloric acid.
The hydrochloric acid in the stomach makes the ph too acidic for enzymes in the small intestines to work properly
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write down the word equation for aerobic respiration
glucose + oxygen----- carbon dioxide + water + energy
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Give two examples of how animals use the energy produced during aerobic respiration
1) to build up larger molecules from smaller ones 2) In animals, to allow the muscles to contract
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What is the word equation for anaerobic respiration
glucose ----- energy + lactic acid
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Explain how you repay an oxygen debt.
hard breathing for a while, to get more oxygen into your blood. Blood flows through your muscles to remove the lactic acid by oxidising it to harmless co2 and water.
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Give two kinds of enzyme that would be useful in a biological washing powder
proteases and lipases.
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Discuss the advantages and disadvantages of using enzymes in industry
lower cost, v specific, work for a long time, and biodegradable but people develop allergies to the enzymes, enzymes can be denatured by even a small increase in temp. Enzymes can also be v expensive.
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Explain how DNA controls activities in a cell.
Genes (in DNA) simply tell the cells in what order to put the amino acids together, which determines what proteins the cell produces.
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Explain how DNA fingerprinting is used in forensic science
Dna finger printing is a way of cutting up a persons Dna into small sections and then separating them. Every persons genetic finger printing has a unique pattern, this means you can tell people apart.
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What is mitosis used for in the human body
Mitosis makes new cells for growth and repair.
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describe the 4 steps of mitosis
1) in a cell thats not dividing, the DNA is all spread out in long strings 2) If the cell gets a signal to divide it will duplicate its DNA- so there's one copy for each new cell. The DNA is copied and forms x-shaped chromosomes.
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describe the 4 steps of mitosis (2)
Each 'arm' of the chromosome is an exact duplicate of the other. 3) the chromosomes then line up at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to the opposite ends of the cell.
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Describe the 4 steps of mitosis (3)
3) membranes form around each of the sets of chromosomes. These become the nuclei of the two cell. Lastly the cytoplasm divides. You now have two new cells containing exactly the same DNA- there identical.
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Name the other type of cell division, and say where it happens in the body of a human male.
Meiosis takes place in the testes.
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what is differentiation in a cell?
the process by which a cell changes to become specialised for its job.
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Give 3 ways that embryonic stem cells could be used to cure diesis.
bone marrow transplants can be done because bone marrow contains stem cells which can turn into new cells, which someone sick may be missing.
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which chromosome in the human body causes male characteristics?
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List 3 important conclusions that Mendel reached following his experiments with pea plants
1) characteristics in plants are determined by 'hereditary units' 2) hereditary units are passed on from both parents, one unit from each parent. 3) hereditary units can be dominant or recessive- if an individual has both the dominant and the recess
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3 conclusions of mendel continued
unit for a characteristic, the dominant allele will be expressed.
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The significance of mendels work was not realised untill 1900, 16 years after mendel died. Why was the importance of his work not understood?
in mendels time they did not know that the 'hereditary units' are course genes, but in his time they did not know about genes or DNA.
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what is an allele?
an allele is a different version of a gene.
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what is meant by the term heterozygous and homozygous?
if an organism has two alleles for a particular gene the same then its homozygous. If an organism has its two alleles for a particular gene are different then it is heterozygous.
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Describe the main difference between a recessive allele and a dominant one
If the characteristic is shown it is dominant with a capital letter. To display a dominant characteristic the organism can be either CC or Cc. But for a recessive (small letters ) to be shown both its alleles have to be recessive.
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If both parents carry recessive allele for cystic fibrosis, what is the probability of their child being a carrier?
1 in 4
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what is polydactyly?
a genetic disorder where a babys born with extra fingers or toes.
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describe the 3 ways that fossils can form. Give an example of each type.
1) From gradual replacement of minerals 2) from casts and impressions eg. footprints 3) from preservation in places where no decay happens eg. amber and tar pits.
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What is speciation? explain how geographical isolation can lead to
isolation is wherre populations of a species are sperated. By physical barrier eg. floods, so geographical isolation. Different conditions so different adaptions so they become different species.
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Card 2


what 2 parts do plant cells have that animals dont?


chloroplasts, cell wall, permanent vacuole

Card 3


what does the nucleus do?


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Card 4


what does the cytoplasm do?


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Card 5


What does the cell membrane?


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