B6 Beyond the Microscope

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Bacteria reproduce by splitting into two in a type of asexual reproduction called _____ ______
Binary Fission
1 of 40
In terms of numbers, why are bacteria so successful?
They can survive on an enormous range of energy sources, live in a very wide range of habitats and some bacteria live by taking in organic nutrients but others can make there own food.
2 of 40
Yeast is a single-celled fungus. How can the growth rate of yeast be altered?
Changing food availibilty, changing temperature, changing pH and removing waste products.
3 of 40
The growth rate of yeast doubles for every ___ rise in temperature until optimum is reached.
10°c
4 of 40
Explain how a virus reproduces. (Viruses are not living cells but very small structures made of a protein coat surrounding a strand of genetic material)
It will attach itself to a specific host cell, inject its genetic material into the cell, use the cell to make the components of new viruses and cause the host cell to split open and die to release the virus.
5 of 40
Describe how the structure of a virus is different from that of a typical bacterium
No cell membrane, no flagellum and no cytoplasm
6 of 40
What are the four stages of an infectious disease?
The microbe enters the body, it reproduces many times without causing symptoms (incubation period), the microbes cause the production of many toxins and the toxins cause symptoms, such as fever.
7 of 40
____ are used on the outside of the body to kill microbes and prevent their entry. ___ tend to be used inside the body to kill microbes once they have entered.
Antiseptics; Antibiotics
8 of 40
How do doctors try to prevent antibiotic resistance?
Only pescribe when antibiotics are really necessary. They advise patients to always finish the dose so partially resistant bacteria are killed.
9 of 40
Penicillin is produced by a type of organism. Which type and who discovered it?
Fungus and Sir Alexander Fleming
10 of 40
Explain how yoghurt is made
First, all the equipment is sterilised. Then the milk is pasteurised by heating it to about 78°c.When the milk is cooled down it is incubated with a culture of bacteria. This is followed by sampling and then adding flavours, colours and packaging.
11 of 40
The type of ___ that is added to the milk is ____. This causes the breakdown of lactose into lactic acid, which makes the yoghurt taste acidic.
Bacterium; Lactobacillus
12 of 40
Why is it important to pasteurise beer?
To kill any harmful bacteria
13 of 40
The process of fermentation in yeast involves anaerobic respiration. What is the word and symbol equation for fermentation?
glucose(sugar) -> ethanol (alcohol)+carbon dioxide. C6H1206 -> 2C6H5OH + 2CO2
14 of 40
Yeast can be used in brewing beer or wine. Explain the process
First, sugar is extracted from grapes or barley seeds. Then yeast added. It is kept warm to allow it to ferment. The wine or beer is allowed to clarify (clear) the liquid is then removed from yeast sediment. Drink may then be pasteurised and bottled.
15 of 40
What are three advantages of using biofuels over fossil fuels?
Renewable energy source, no increase in greenhouse gas levels and no particulates are released.
16 of 40
A biofuel is a mixture of alcohol and petrol. What name is given to this?
Gasohol
17 of 40
Why is gasohol more economically viable in some countries than others?
Higher supply of sugar and lacking in natural oil reserves.
18 of 40
What does biogas contain?
Mainly methane, some carbon dioxide and very small amounts of hydrogen, nitrogen and hydrogen sulfate.
19 of 40
Biogas production is affected by temperature because as the temperature increases, the bacteria multiply ___ and the ____ within them work better. Above 45°c, the _____ are denatured and the bacteria die.
Faster; enzymes; enzymes
20 of 40
Soil contains dead organic material. What is the name given to the decomposed organic material found in soil?
Humus
21 of 40
If a soil has ____ particles, then the air content and the permeability is usually ____. If a soil has larger amounts of ___ it will often hold ___ water and air.
Larger; Higher; Humus; More
22 of 40
What experiments can be used to compare different soil samples?
Humus content can be found by burning off the humus using a bunsen. Air content can be found by seeing how much water is need to fill the air spaces. Water content can be found by slowing heating the soil to evaporate the water.
23 of 40
Why are earthworms important to soil structure and fertility?
They bury organic material for decomposition by bacteria ad fungi, aerate and drain the soil, mix up soil layers and neutralise acid soil
24 of 40
Why is it important to have humus in the soil?
It will decompose to release minerals and increase the air content of the soil.
25 of 40
What is one advantage and one disadvantage of living in water?
Ad: No dehydration/water supports weight/ little temperature change. Dis: Difficult to maintain water balance/ difficult to move against current
26 of 40
Amoeba are microscopic animals that live in fresh water. The water they live in is more dilute than their cytoplasm.Explain why this is a problem
Water will enter their cytoplasm by osmosis
27 of 40
Why do chemicals like PCB's and DDT kill animals at the top of the food chain?
They are toxic, do not break down quickly and so accumulate and become concentrated higher up in the food chain and affect animals with a long life span, such as whales.
28 of 40
Organisims such as amoeba have a ____ _____ that can store any excess water. The vacuole can then fuse with the cell membrane and empty the water to the outside.
Contractile vacuole
29 of 40
What are organisms which a sensitive to pollution used for?
Biological Indicators for pH and oxygen.
30 of 40
What enzymes do washing powders use?
Amylase (to digest carbohydrates such as starch), Lipase (to digest fat and remove fatty stains), Protease (to digest protein and remove protein stains)
31 of 40
Biological washing powders may not work in acidic or alkaline tap water because this is not the ____ for the enzymes and they might start to ____.
Optimum; Denature
32 of 40
Sucrase is an enzyme used to breakdown sucrose. Explain why this enzyme is useful to the food industry and the word equation for the action of sucrase.
Breakdown products of sucrose are sweeter than just sucrose so less is needed. sucrose -> glucose + fructose
33 of 40
Describe two advantages of immobilising enzymes
Easier to separate enzyme from product, less purification needed, enzyme can be reused, continuous so is cheaper
34 of 40
Immobilised enzymes can be used to make lactose-free milk. What is the name of the enzyme used to make lactose-free milk?
Lactase
35 of 40
Which type of enzyme is needed to remove DNA from the organism?
Restriction enzymes
36 of 40
Explain how a DNA fingerprint is made
Extraction of DNA from sample, fragmentation of DNA using restriction enzymes, separation using electrophoresis, visualising pattern using a radioactive probe.
37 of 40
Describe how scientists check which bacteria have taken up the human insulin gene
Using a assaying technique, include gene for antibiotic resistance and then flood bacteria with antibiotic, chose bacteria that has survived.
38 of 40
Scientists can change DNA of an organism. What is the term used to describe an organism that has had its DNA changed?
Transgenic
39 of 40
What are the three stages of changing the DNA of an organism?
First a section of DNA (a gene) is removed from one organism. Then, you cut open the DNA of the second organism and then you add the DNA from the first organism to the second one.
40 of 40

Other cards in this set

Card 2

Front

In terms of numbers, why are bacteria so successful?

Back

They can survive on an enormous range of energy sources, live in a very wide range of habitats and some bacteria live by taking in organic nutrients but others can make there own food.

Card 3

Front

Yeast is a single-celled fungus. How can the growth rate of yeast be altered?

Back

Preview of the front of card 3

Card 4

Front

The growth rate of yeast doubles for every ___ rise in temperature until optimum is reached.

Back

Preview of the front of card 4

Card 5

Front

Explain how a virus reproduces. (Viruses are not living cells but very small structures made of a protein coat surrounding a strand of genetic material)

Back

Preview of the front of card 5
View more cards

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pj.c

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Wonderful! Thank you.

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