Biology - Topic 1 - Key Concepts in Biology Flashcards
Whatdoesamicroscopedo?
makessmallobjectsappearlarger/magnifiessmallobjects
Whatpartofamicroscopedoyoulookthrough?
eyepiecelens
Whichpartofamicroscopedoyouusetogetaclearimage?
thefocusingwheel
Puttheseinorderofsize,biggestfirst:atom,animalcell,cellnucleus,muscletissue,proteinmolecule,watermolecule
muscletissue,animalcell,cellnucleus,proteinmolecule,watermolecule,atom
Amicroscopehasa×5eyepiecelensanda×5objectivelens.Whatisthetotalmagnification?
×25;5×5=25
Ahumanhairhasawidthof100µmbutappears20mmwideinaphoto.Whatmagnificationisthephoto?
×200;20mm=20000µm;20000÷100=200
Howmanymillimetresarethereinametre?
1000
Whatunitis1000timessmallerthanamillimetre?
micrometre,µm
Whatistheunitsymbolforananometre?
nm
Name one part you could find in a plant cell but not an animal cell.
cell wall, chloroplasts, permanent vacuole
What process happens in a mitochondrion?
aerobic respiration
What is one function of a plant cell’s permanent vacuole?
to help keep the cell rigid/to store substances
In which part of a plant cell is cell sap stored?
vacuole
In which part of a cell would you find chromosomes?
nucleus
When you look down a microscope, what is the area that you see called?
field of view
Why can an electron microscope detect smaller structures in cells than a light microscope?
it has better magnification and better resolution
What is a picture taken with a microscope called?
micrograph
Some microscope pictures have a small line drawn on them with information about how long the line is when unmagnified. What is this line called?
scale bar
List three sub-cellular structures that are usually
found in animal cells.
cell membrane, nucleus, mitochondria, ribosomes
Which cell structure controls what enters and leaves the cell?
cell membrane
Which cell structure controls how the cell works?
nucleus
Which plant cell structure contains chlorophyll?
chloroplast
What is the function of the cell structure that contains chlorophyll?
to capture energy from light for photosynthesis/to produce glucose using photosynthesis
Describe the function of the cell wall
supports and protects the cell
What is the function of ribosomes?
manufacture of proteins
What are gametes?
sex cells
A bacterium is 20 µm long. How long is it in metres?
0.00002 m
A bacterium is 5 µm wide. How wide is it in nanometres?
5000nm
What do bacteria use to move themselves?
flagella
Animal and plant cells are eukaryotic. What word describes bacterial cells?
prokaryotic
Name one structure that an animal cell would have but a bacterial cell would not.
nucleus, mitochondria
What is 1 × 10^6m written as an ordinary number?
1 000 000 m
Name two substances that might be found in the cytoplasm of an egg cell to provide energy.
carbohydrate or starch, lipid or fat or oil
In which system of the body is food broken down?
digestive system
Why do we need to break food down?
because the molecules in food are too large to cross cell membranes
In which organ of the body is digested food absorbed?
small intestine
Which group of molecules help to digest food?
enzymes
Name an example of an enzyme
amylase, protease, lipase
What does a sperm cell use enzymes for?
to digest a path through the jelly coat of the egg cell
Do plants contain enzymes?
yes – they control many reactions inside plant cells
Name a part of a plant where you might find
enzymes.
anywhere a reaction takes place, e.g. in chloroplasts for photosynthesis, in mitochondria for respiration, where starch grains are made
What nutrient is starch an example of?
carbohydrate
Why are proteins and carbohydrates examples of polymers?
They are made up of many similar molecules/monomers.
Which monomers make up starch?
glucose
Which monomers make up a protein?
amino acids
Are enzymes carbohydrates, proteins or lipids?
proteins
Which group of substances are fats and oils examples of?
lipids
Name one food that contains a lot of starch.
potato, pasta, bread, rice
What effect does the enzyme amylase have on starch?
breaks it down to small sugars
Food provides nutrients for growth. What else is it a source of, which we need for activity?
energy
What are the subunits (small molecules) that make up carbohydrates?
simple sugars, e.g. glucose
Which two kinds of subunits form lipids (fats and oils)?
fatty acids and glycerol
Which subunits make up enzymes?
amino acids
Amylase is a kind of enzyme. Where is it found?
mouth/salivary glands and small intestine/pancreas
Why are enzymes called biological catalysts?
They are molecules found inside living organisms that speed up the rate of reactions.
What is a substrate?
A molecule that is changed in a reaction
What is the substrate for amylase?
starch
Starch synthase is an enzyme that catalyses the synthesis of starch. Explain what this means.
The enzyme combines with subunits/small sugar molecules and helps them join together to form starch.
Why do different enzymes have different 3D shapes?
The amino acids are arranged in a different order in different proteins.
Which kind of large organic molecule does a protease digest?
proteins
What is the name of the part of an enzyme into which the substrate fits?
active site
Why do most enzymes only work with one
substrate?
Only substrates with the same shape as the active site can sit in the site and take part in the reaction.
Enzymes are specific to their substrate. What does
this mean?
The enzyme will only work with particular substrates -those substrates that have the right shape.
Which term describes an enzyme in which the active site has permanently changed shape?
denatured
What effect does a large change of shape of an enzyme’s active site have on how the enzyme works?
The enzyme no longer works.
Give two examples of changes in the cell environment that could cause the active site to change shape.
pH, temperature
Carbon dioxide is produced inside a cell and moves out of the cell by diffusion. What does this mean?
there is an overall movement of gas particles from
where there are more of them to where there are fewer
Name two substances that plants take in from the soil through their roots
water and dissolved mineral salts
There is a 5% sucrose solution and a 10% sucrose solution. Which solution has the higher concentration of sucrose?
10% solution
Two beakers contain the same volume of solution. One is a 10% sodium chloride solution, the other is a 5% sodium chloride solution. Which beaker contains more water molecules?
5% solution
Which solution is used to test for starch and what is the positive result?
Iodine solution turns from brown to blue/black
Which solution is used to test for protein and what is the positive result?
Biurets solution turns from blue to purple
What solution is used to test for reducing sugars and what is the positive result?
Benedicts solution, once heated, turns from blue to green/orange/red
What solution is used to test for lipids and what is the positive result?
Ethanol turns from clear to cloudy.
