not being tested Flashcards
what is the formula for calculating the magnification of an image?
…………………………….image size
magnification = __________
………………………………real size
what is diffusion?
the net passive movement of particles down the concentration gradient from an area of high concentration to an area of low concentration
will a bigger concentration gradient increase or decrease the rate of diffusion?
increase
will a higher temperature increase or decrease the rate of diffusion
increase
what is osmosis?
the movement of water particle across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
is osmosis a type of diffusion?
yes
what does the surface area to volume ratio affect?
how easy it is for an organism to exchange substances with its environment
what is the formula that links image size, real size, and magnification?
image size = real size x magnification
what is the formula for total magnification?
total magnification = eyepiece magnification x objective lens magnification
how do viruses make you feel ill?
they live inside your cells and replicate themselves using the cells’ machinery to produce many copies of themselves. The cell will usually then burst, releasing all the new viruses. This cell damage is what makes you feel ill
what are protists?
single-celled eukaryotes
what are hyphae?
thread-like structures that make up the body of some fungi. Hyphae can grow and penetrate human skin and the surface of plants, causing diseases. Hyphae can also produce spores, which can be spread to other plants and animals
name three ways pathogens can be spread
- Water - some pathogens can be picked up by drinking or bathing in dirty water
- Air - pathogens can be carried in the air and can then be breathed in
- Direct contact - some pathogens can be picked up by touching contaminated surfaces, including the skin
Is measles fungal, viral or caused by a protist
viral
how is measles spread?
by droplets from an infected person’s sneeze or cough
what are the symptoms of measles?
a red skin rash and a fever
name two possible complications of measles
measles can sometimes lead to pneumonia (a lung infection) or a brain infection called encephalitis
is HIV a virus, a fungus, or caused by a protist
a virus
how is HIV spread
by sexual contact, or by exchanging bodily fluids such as blood.
what are the symptoms of HIV?
HIV initially causes flu-like symptoms for a few weeks. Usually, the person doesn’t then experience any symptoms for several years. The virus attacks the immune cells, and if the body’s immune system is badly damaged it can’t cope with other infections or cancers. At this stage, the virus is known as late stage HIV infection, or AIDS
How can HIV be controlled?
with antiretroviral drugs, which stop the virus replicating in the body
what virus causes a mosaic pattern on the leaves of the plants?
Tobacco mosaic virus
what are the symptoms/signs of tobacco mosaic virus?
parts of the leaves become discoloured, which means the plant can’t carry out photosynthesis as well, so the virus affects growth
what is an example of a fungal disease?
Rose black spot
what is rose black spot?
a fungus that causes purple or black spots to develop on the leaves of rose plants. The leaves can then turn yellow and drop of
why is rose black spot bad for the plant?
it means that less photosynthesis can happen, so the plant doesn’t grow very well
how does rose black spot spread?
it spreads through the environment in water or by the wind
how is rose black spot treated?
using fungicides and by stripping the plant of its affected leaves. These leaves then need to be destroyed so that the fungus can’t spread to other rose plants
name an example of a disease caused by a protist
malaria
how do mosquitos pick up a malarial protist?
by feeding on an infected animal
how do mosquitos infect other animals with malaria?
every time the mosquito feeds on another animal, it infects in by inserting the protist into the animal’s blood vessels
what does malaria cause? (symptom-wise)
repeating episodes of fever. It can be fatal.
how can the spread of malaria be reduced?
by stopping the mosquitos from breeding
how can people be protected from mosquitos?
by using insecticides and mosquito nets
how can destroying vectors help to reduce the spread of a disease?
by getting rid or the organisms that spread disease you can prevent the disease from being passed on. Vectors that are insects can be killed using insecticides or by destroying their habitat so that they can no longer breed
why does your skin secrete antimicrobial substances?
to kill pathogens
what are three things white blood cells could do when they detect a pathogen?
- white blood cells engulf foreign cells and digest them.
- produce antibodies
- produce antitoxins
what is phagocytosis?
the process of white blood cells engulfing foreign cells and digesting them
how do white blood cells produce antibodies?
- every invading pathogen has unique molecules (antigens) on its surface
- when some types of white blood cells come across a foreign antigen they start to produce antibodies to lock onto the invading cells so that they can be found and destroyed by other white blood cells
- antibodies are then produced rapidly and carried around the body to find all similar bacteria or viruses
- if the person is infected with the same pathogen again the white blood cells will rapidly produce the antibodies to kill it - the person is naturally immune to that pathogen and won’t get ill
what do antitoxins do?
counteract toxins produced by the invading bacteria
what are the five main ways that plants use glucose?
- for respiration
- making cellulose
- making amino acids
- stored as oils or fats
- stored as starch
do plants carry out respiration?
yes
how is glucose used to make amino acids?
glucose is combined with nitrate ions (absorbed from the soil) to make amino acids, which are then made into proteins
where is starch stored in plants?
roots, stems and leaves
what are the five main ways that plants use glucose?
- for respiration
- making cellulose
- making amino acids
- stored as oils or fats
- stored as starch
what is an “oxygen debt”?
the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from the cells
what are two ways we deal with the build up of lactic acid from anaerobic respiration?
- pulse and breathing rate stay high while there are high levels of lactic acid and CO2 to get more oxygen to your cells to react with the lactic acid
- the blood transports the lactic acid from your muscles to the liver, where it is converted back into glucose
