The Nature and Variety of Organisms Flashcards
what are the 8 basic characteristics all living organisms share in common?
- they need nutrition
- they respire
- they excrete their waste
- they respond to their surroundings
- they move
- they can control their internal conditions
- they reproduce
- they grow and develop
why do living organisms need nutrition?
to provide them with energy and for growth and repair
what are 5 different examples of nutrients?
- proteins
- fats
- carbohydrates
- vitamins
- minerals
why do organisms need to respire?
to release energy from their food
why do organisms need to respond to their surroundings?
because living organisms have the ability react to changes in their surroundings
why do organisms need to move?
they can move toward things like water and food, but, they can also move away from things like predators and poisons. Even plants can move a bit
why do organisms need to control their internal conditions?
they need to control it for their own well being. Internal conditions includes temperature and water content
why do organisms need to reproduce?
they have to produce offspring (children) in order for their species to survive
why do organisms need to grow and develop?
they have growth and development so that they can grow into their adult form
why do organisms need to excrete their waste?
so that waste products such as carbon and urine are removed, this removal is called excretion
what are organisms made up of?
of cells (they are like tiny building blocks)
what are the two types of cells?
eukaryotic and prokaryotic
how are eukaryotic cells?
they are complex and include all animal and plant cells
how are prokaryotic cells?
they are smaller and simpler cells (e.g bacteria)
describe the image of a animal cell
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what are organelles?
specialised structures that perform various jobs inside cells.
what are 5 typical organelles found in cells?
- nucleus
- cytoplasm
- ribosomes
- cell membrane
- mitochondria
what does the nucleus do and contain?
it contains genetic material that control’s the cell’s activities. It is surrounded by its own membrane
what does the ribosomes do and contain?
small organelles where proteins are made in the cell
what does the cell membrane do and contain?
this membrane forms the outer surface of the cell and controls the substances that go in and out
what does the mitochondria do and contain?
they are small organelles where most of the reaction for aerobic respiration takes place. Respiration transfers energy that the cell needs to work
what does the cytoplasm do and contain?
it is a gel-like substance where most of the cell’s chemical reactions happen. It contains enzymes which control these reactions
describe the image of a typical plant cell
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what are the 8 typical organelles a plant cell contains?
- nucleus
- cytoplasm
- ribosomes
- cell membrane
- mitochondria
- chloroplasts
- vacuole
- cell wall
what does the chloroplast do?
photosynthesis, which is what makes food for plants. Chloroplasts contain a green substance called chlorophyll which is used in photosynthesis
what does the vacuole do?
it is a large organelle that contains cell sap (a weak solution of sugars and salts). It helps to support the cells
what does the cell wall do?
it is rigid structure made of cellulose, which surrounds the cell membrane. It supports the cell and strengthens it
how many cells do some organisms consist of?
one cell
what does multicellular mean?
contains lots of cells
what do multicellular organisms need to stay in order?
some form of organisation
what is a tissue?
a group of similar cells that work together to carry out a particular function
how many cell types can a system contain?
more than one
what are tissues organised into?
into organs
what is an organ?
a group of different tissues that work together to perform a function
what are organs organised into?
an organ system
what does an organ system mean?
organs working together. Each system does a different job
living organisms are arranged into groups according to what?
the features they have in common
what are the 6 groups organisms are arranged to?
- plants
- animals
- fungi
- protoctists
- bacteria
- viruses
what type of organisms are plants, animals and fungi?
eukaryotic organism, because they are made of eukaryotic cells
what are the 4 important descriptions of plants?
- plants are multicellular
- they have chloroplast which means they can photosynthesise
- their cells have cell walls, meaning they are made of cellulose
- plants store carbohydrates as sucrose or starch
what are the 6 important descriptions of animals?
- animals are multicellular
- they don’t have chloroplasts and can’t photosynthesise
- their cells don’t have cell walls
- most have some kind of nervous coordination, meaning they can respond rapidly to changes in their environment
- they can usually move around from one place to another
- they often store carbohydrate in the form of glycogen
what are the 6 important descriptions of fungi?
- some are single-celled
- other have a body called mycelium which is made up of hyphae (thread like structures). The hyphae contains lots of nuclei
- they can’t photosynthesise
- their cells have cell walls made of chitin
- most feed by saprotrophic nutrition
- they can store carbohydrate as glycoge
what are 2 examples of plants?
- cereals
- herbaceous legumes
what are 2 examples of animals?
- mammals
- insects
what are 2 examples of fungi?
- yeast
- mucor
what are the 3 important descriptions of protoctists?
- they are single-celled and microscopic
- some have chloroplasts and are similar to plant cells
- others are more like animal cells
what are the 5 important descriptions of bacteria?
- they are single-celled and microscopic
- they don’t have a nucleus
- they have a circular chromosome of DNA
- some can photosynthesise
- most bacteria feed off other organisms, both living and dead
what are the 5 important descriptions of viruses?
- they are particles not cells and are smaller than bacteria
- they can only reproduce inside living cells, it is an example of a parasite
- they infect all types of living organisms
- they come in loads of different shapes and sizes
- they don’t have a cellular structure they have a proteins coat around some genetic material (either DNA or RNA)
what are pathogens?
organisms that cause disease
what are 4 examples of pathogens?
fungi, protoctists, bacteria and viruses
what do living things have happening inside them all the time?
thousands of different chemical reactions
why do chemical reactions need to be carefully controlled?
to get the right amount of substances in the cells
how do you make reactions happen more quickly?
by raising the temperature
why is there a limit of how far you can raise the temperature inside a living creature?
because cells can start to get damaged
what do enzymes do?
they make chemical reactions work
what are catalysts?
it is a substance which increase the speed of a reaction, without being changed or used up in the reaction
what are enzymes used for?
to reduce the need for high temperatures. We only have enzymes to speed up the useful chemical reactions in the body, these are called metabolic reactions
what are enzymes?
they are proteins made up of chains of amino acids. These chains are folded into unique shapes, which enzymes need so that they can do their jobs
what are the two things that can help chemical reactions?
being split apart or joined together
what is a substrate?
a molecule that is changed in a reaction
what does every enzyme molecule have?
an active site
what is an active site?
the part where a substrate joins on to the enzyme
how many reactions do enzymes usually speed up?
one reaction
why do enzymes usually speed up only one reaction?
because for an enzyme to work, a substrate has to be the correct shape to fit into the active site
what is a lock and key mode?
when the substrate fits into the enzyme just like a key fits into a lock
describe how a lock and key diagram looks like
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what do enzymes need to work properly?
the right conditions
what happens to enzymes when temperatures are changed?
it changes the rate of enzymes catalysed reaction
what do enzymes act as?
they act as biological catalysts
what is the process of the rate of enzymes when temperature is increased?
at first the rate of enzymes increase, until it get to the optimum temperature (where the enzyme is most active), and from there, the enzymes rate decreases because the bonds holding them together break
what other than temperature affects enzymes?
pH
what happens to enzymes if the pH is too high or too low?
the pH interferes with the bonds holding enzymes together, this changes the shape of the active site and denatures the enzyme
what is usually the optimum pH for enzymes (where they work their best)?
neutral pH 7
Practical: measuring how fast a product appears depending on temperature
(7 steps)
1) the enzymes catalase catalyses the breakdown of hydrogen peroxide into water and oxygen
2) you can collect and measure how much is produced in a set time
3) use a pipette o add a set amount of hydrogen peroxide to a boiling tube in a water bath at 10 degrees
4) set up the rest of the apparatus as shows (page 11). Add a source of catalase to the hydrogen peroxide and quickly attach the bung
5) record how much oxygen is produced in the first minute. Repeat tree times and calculate the mean
6) repeat at 20, 30, and 40 degrees
7) control any variable to make it a fair test
Practical: measure how fast a substrate disappears
5 steps
1) the enzyme amylase catalyses the breakdown of starch to maltose
2) it is easy to detect a starch using iodine solution, if starch is present, the iodine solution will change from browny-orange to blue-black
3) set up the apparatus shown in the diagram. Put a drop of iodine solution into each well on the spotting tile
4) every 10 seconds, drop a sample of the mixture into a well using a pipette. When the iodine solution remains browny-orange (starch is no longer present) record the total time take
5) repeat with the water bath at different temperature to see how it affects the time taken for the starch to be broken down
what is diffusion?
it is the gradual movement of particles from places where there are lots of them to places where there are fewer (the natural tendency for stuff to spread out)
what does it mean when you say diffusion is a passive process?
that it doesn’t acquire any energy
in which states of matter can diffusion happen in?
liquids and gases, because the particles in these substances are free to move randomly
why are cell membranes clever?
because they let stuff in and out
what are osmosis?
the net movement of water molecules across a partially permeable membrane from a region of higher concentration to a region of lower water concentration
how does water move in and out of cells?
through the osmosis
what do tissue fluid surround?
the cells in the body
Practical: investigating diffusion in a non-living system
1) make up some agar jelly with phenolphthalein and dilute sodium hydroxide -> making the jelly pink
2) put some dilute hydrochloric acid in a beaker
3) cut out a few cubes from the jelly and put them in the beaker of acid
4) if you leave the cubes for a while they’ll eventually turn colourless as the acid diffuses into the agar jelly and neutralises the sodium hydroxide
