Topic One Flashcards
Key Concepts in biology
What does a microscope do?
Makes small objects appear larger/magnifies small objects
What part of a microscope do you look through?
eyepiece lens
Which part of a microscope do you use to get a clear image?
the focusing wheel
If an average height person in Year 10 is magnified 600 times, how tall will they be compared to the tallest building in the world, which is 828 m tall?
about the same height; the Burj Khalifa, Dubai is 828 m tall
Put these in order of size, biggest first: atom, animal cell, cell nucleus, muscle tissue, protein molecule, water molecule
muscle tissue, animal cell, cell nucleus, protein molecule, water molecule, atom
A microscope has a ×5 eyepiece lens and a ×5 objective lens. What is the total magnification?
×25; 5 × 5 = 25
A human hair has a width of 100 μm but appears 20 mm wide in a photo. What magnification is the photo?
×200; 20 mm = 20 000 μm; 20 000 ÷ 100 = 200
How many millimetres are there in a metre?
1000
What unit is 1000 times smaller than a millimetre?
micrometre, μm
What is the unit symbol for a nanometre?
nm
What is an estimation?
an approximate value
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.
any three from: cell membrane, nucleus, mitochondria,
List three sub-cellular structures found in plant cells but not in animal cells.
large permanent vacuole, chloroplasts, cell wall
Which cell structure controls what enters and leaves the cell?
cell membrane
Which cell structure controls how the cell works?
nucleus
In which cell structure does respiration mainly take place?
Mitochondria
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 structure that surrounds plant cells, but not animal cells.
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?
500 nm
What part of an animal cell controls the cell’s activities?
Nucleus
What do ribosomes make?
Proteins
Name one part that a plant cell might have but an animal cell would not.
chloroplast, permanent large vacuole, cell wall
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 this format for numbers called: A × 10n?
Standard form
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
Egg cells also contain protein. Which cell structure makes proteins?
ribosome
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
Give one example of the group of molecules that you named in the previous question.
any suitable example, such as 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 anywhere a reaction takes place
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.
any suitable example such as: potato, pasta, bread, rice
What effect does the enzyme amylase have on starch?
breaks it down to small sugars/maltose
Food provides nutrients for growth. What else is it a source of, which we need for activity?
energy
Which cell structures break down molecules from food to release energy?
mitochondria
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 kind of large biological molecule are enzymes?
Proteins
Which subunits make up enzymes?
Amino acids
Amylase is a kind of enzyme. Where is it found in humans?
mouth/salivary glands and small intestine/pancreas
What is a catalyst?
A molecule that speeds up the rate of a reaction
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.
What are the subunits of enzymes?
amino acids
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
Which kind of enzyme would break down a food stain made by sunflower oil?
lipase
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
Which cell structure surrounds every kind of cell?
cell surface membrane
What is the function of this cell structure?
to control what enters and leaves the cell
Name one gas that a cell needs to take in from its surroundings, and explain your answer.
oxygen needed for respiration/to release energy in mitochondria; carbon dioxide needed for photosynthesis
Name one other substance that a cell needs to take in from its surroundings, and explain your answer.
any suitable answer, such as glucose/sugar needed for respiration
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 one other substance that is made inside a cell and leaves the cell.
any suitable substance, such as enzymes or hormones that are secreted
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
What is the cell membrane responsible for?
Determining which bits go in and out of the cell
What is the cell wall important for?
Structure
What is the vacuole important for?
Structure
What happens in the cytoplasm?
Most of the reactions take place
What are the ribosomes responsible for?
Protein synthesis
What are the chloroplasts responsible for?
Photosynthesis
What is produced in the mitochondria?
Energy is released in respiration
What is the nucleus?
The control centre of the cell, where the DNA is held
True/False: Plant cells have a nucleus
True
True/False: Plant and animal cells both have a cell membrane
True
True/False: Plant and animal cells both have a cell wall
False, only the plant cell has a cell wall
True/False: Plant and animal cells both have mitochondria
True
True/False: Plant and animal cells both have chloroplasts
False, only the plant cell has chloroplasts
Give 3 features of an animal cell
Any 3 from cell membrane, mitochondria, ribosomes, cytoplasm and nucleus
Give 5 features of a plant cell
Any 5 from nucleus, cell membrane, cell wall, vacuole, cytoplasm, ribosomes, chloroplasts, mitochondria
Give 3 features that animal cells and plant cells have in common
Any 3 from cell membrane, nucleus, cytoplasm, mitochondria and ribosomes
True/False: The chromosomal DNA is found in the nucleus
False, it is not in the nucleus
What is the flagella used for?
Locomotion
Neurons look very similar/different to muscle cells
Different
True/False: All cells look the same
False
How do villi make a cell specialised for its job?
Give long surface area
Muscle cells need to be able to stretch and ________
contract
All cells start off looking different/the same
the same
What happens during differentiation?
Various different genes are turned on and off so the cell will start to specialise
What happens when a cell starts to specialise?
It’ll grow a really long axon/grow villi/turn into a leaf cell - whatever is needed for the cell to be specialised
What is the equation that links magnification, image height
Magnification = image height / object height
1 centimeter = ? meters
1 x 10-2
1 millimeter = ? meters
1 x 10-3
1 micrometer = ? meters
1 x 10-6
1 nanometer = ? meters
1 x 10-9
1 picometer = ? meters
1 x 10-12
What are the units for centimeters?
cm
What are the units for millimetres?
mm
What are the units for micrometers?
μm
What are the units for nanometers?
nm
What are the units for picometers?
pm
Amalyse, protease and lipase are all _______
enzymes
Enzymes have a very specifically shaped ______ ____
active site
site
Only the substate(s) that have the complimentary ____ will fit in the active site of an enzyme
When the substrate and the enzyme meet, this makes…
An enzyme-substrate complex
What happens after the enzyme-substrate complex is formed?
The enzyme will either break things part or join things together
What does the enzyme do after it has broken things apart/joined things together?
Release the product
Can the enzyme be used again after it has released the product?
Yes, it is unchanged
True/False: Temperature affects enzyme activity
True
At low temperatures there is not enough/too much energy
Not enough
At the peak of the enzyme activity graph it is the _______ temperature
optimum
What happens to enzymes when higher than the optimum temperature?
They become denatured
What does it mean when an enzyme denatures?
The links between them holding everything together are being destroyed.
True/False: When an enzyme is denatured, it is killed
False
Is the graph showing how temperature affects enzyme activity lop sided to the left or right, or is it symmetrical?
Lop sided to the right
Is the graph showing how pH affects enzyme activity more lop sided to the left or right, or is it symmetrical?
symmetrical
True/False: There is no optimum pH for enzyme activity
False
What happens to an enzyme when the pH is too high or too low?
The bonds will not be in place so the active site of the enzyme will break down and the enzyme will become denatured
There is a limited/unlimited amount of active sites on an enzyme
Limited
When all the active sites on an enzyme are full up, enzyme activity can/can’t keep increasing
can’t
When the enzyme active sites are filling up, the enzyme activity will increase/decrease substrate concentration
increase
When the active sites are full up, increasing substrate concentration will/won’t increase enzyme activity any further
won’t
An enzyme can be used as a ________
Catalyst
What happens when you use an enzyme as a catalyst?
The reaction will start to happen much faster but will end up at the same point - it will just end faster
Why does use of a catalyst still make a reaction end at the same point as it would without a catalyst?
Due to other limiting factors such as enzyme, substrate or reactant concentration
Lipase breaks down…
fats
Lipase breaks down fats in to…
fatty acids and glycerol
Lipase is made in…
The pancreas and small intestine
Lipase works in the…
Small intestine
Protease breaks down…
Proteins
Protease breaks down proteins in to…
Amino acids
Protease is made in…
The stomach, pancreas and small intestine
Protease works in…
The stomach and small intestine
Amylase breaks down…
Starch
Amylase breaks down starch in to…
Sugars
Amylase is made in…
The salivary glands, pancreas and small intestine
Amylase works in…
The mouth and small intestine
How do you test for fats? (lipids)
Emulsion test or filter paper test
What is the emulsion test?
Add ethanol, shake it and add water. Look for a colour change. If it goes cloudy, lipids are present
What is the filter paper test for fat?
If you rub it on filter paper, the filter paper should go see through
How do you test for starch?
Iodine test
What is the iodine test?
Add iodine. If starch is present it will go a dark black/blue colour
How do you test for additional sugars?
Benedicts test
What is Benedicts test?
Add Benedicts solution, heat it for 2 minutes in a water bath. If it goes red there is lots of sugar and if it goes a pale green/yellow there is little sugar
How do you test for protein?
Biurets test
What is the Biurets test?
Add Biurets solution - it will go purple if protein is present
When talking about diffusion we are talking about things moving from…
a high concentration to an area of low concentration
Diffusion goes up/down the diffusion gradient
Down
True/False: Diffusion can be things moving out of a cell
True
True/False: Diffusion can’t happen in the lungs
False
The thin walls in the lungs are only _ cell thick
1
Carbon dioxide diffuses from the _____
blood
Why does carbon dioxide diffuse from the blood into the lungs?
So it can be breathed out
Carbon dioxide diffuses from the lungs in to the _____
blood
True/False: Diffusion can occur in the gut
True
The thin walls of villi in the gut are only _ cell thick
1
Just like the avioli, the villi in the gut have a very _____ surface area
Large
Digested food moves from the gut cavity in to the _____
blood
Why does digested food move from the gut cavity in to the blood
So it can be taken around the rest of the body
Diffusion is the movement of gases or any particles dissolved in solution moving ____ the concentration gradient from an area of ____ concentration to an area of ___ concentration
down, high, low
True/False: Diffusion is from a low concentration to an area of high concentration
False
What is osmosis?
The movement of water through a partially permeable membrane, from an area of high water concentration to an area of low water concentration
True/False: Osmosis is from a high water concentration to an area of low water concentration
True
The pores in the partially permeable membrane in osmosis are/aren’t large enough for the solute to move through
Aren’t
What can move through the partially permeable membrane in osmosis?
Water
True/False: Osmosis occurs in root hair cells
True
What is active transport?
Movement across a membrane from a low concentration to a high concentration - against the concentration gradient
What does the active transport channel do?
Pick up something it wants from the area of low concentration and move it through the channel to the other side
Where could active transport happen and what with?
Glucose in the gut or minerals in roots
