Biology Flashcards
Cytoplasm
A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.
Chloroplast
Organelle that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis.
Permanent vacuole
Filled with cell sap to help keep the cell swollen.
Mitochondria
Organelles that contains the enzymes for respiration, and where most energy is released in respiration.
Ribosomes
Tiny structures where protein synthesis occurs
Bacteria
Bacteria are all single-celled. The cells are all prokaryotic. This means they do not have a nucleus or any other structures which are surrounded by membranes. Larger bacterial cells may be visible using a light microscope, however an electron microscope would be needed to see the details of the cell organelles.
Specialised cell-sperm
The head contains genetic information and an enzyme to help penetrate the egg cell membrane. The middle section is packed with mitochondria for energy. The tail moves the sperm to the egg. Red blood cells. Contain haemoglobin to carry oxygen to the cells.
Specialised cell- root hair
Plants absorb water from the soil by osmosis. Root hair cells are adapted for this by having a large surface area to speed up osmosis.
Which is the correct calculation for magnification of a light microscope?
Magnification of eyepiece x magnification of objective
What term describes the part of a bacterial cell which provides movement?
Flagella
What name is given to cells in the trachea?
Ciliated cells are found within the trachea. They move to propel mucus from your airway.
What affect does extremely high pH have on enzymes?
Extremely high pH denatures enzymes
What does the term optimum mean for enzyme temperature?
Optimum is the temperature which gives the highest enzyme activity.
What type of enzymes break down carbohydrates?
Carbohydrates are broken down by carbohydrase enzymes
What type of enzymes break down fats?
ipase enzymes
What type of enzymes break down proteins?
Proteins are broken down by protease enzymes
What type of enzyme is amylase?
mylase is a carbohydrase found in saliva in your mouth.
What is the test for reducing sugars?
Benedict’s solution.
What does a calorimeter measure
Calorimeters measure the energy stored within a food.
What is the correct calculation for the rate of an enzyme reaction
The correct calculation for rate of reaction is amount of substrate used / time taken.
What part of a cell controls what enters and exits?
A
Cell membrane
What process involves the movement of water across a membrane?
Diffusion
Describe the structure of a generalised animal cell
the cytoplasm is made from water and is where cellular reactions occur
the nucleus contains genetic material which controls the cell
the membrane controls the movement of molecules into and from the cell
mitochondria are the site of respiration
ribosomes are the site of protein synthesis
Describe the structure of a generalised plant cell
the cytoplasm is made from water and is where cellular reactions occur
the nucleus contains genetic material which controls the cell
the membrane controls the movement of molecules into and from the cell
mitochondria are the site of respiration
ribosomes are the site of protein synthesis
the cell wall is made from cellulose and provides support
photosynthesis occurs in chloroplasts
cell sap is stored in the permanent vacuole
What conditions can denature an enzyme?
high temperatures
extreme (very high or low) pH
Describe the structure of a prokaryotic cel
all bacteria possess prokaryotic cells
they do not have a nucleus
instead their DNA is present in the cytoplasm
the cytoplasm is made from water and is where cellular reactions occur
the membrane controls the movement of molecules into and from the cell
flagella rotate or move like whips to move bacterial cells
a cell wall provides protection
Describe the differences between light and electron microscopes.
light microscopes are lower magnification
they are also lower resolution
light microscopes can study living cells but electron microscopes cannot
electron microscopes are more expensive
transmission electron microscopes look at cross sections of samples
scanning electron microscopes look at samples in three dimensions
Describe where enzymes of the digestive system are produced
carbohydrase enzymes are produced in the mouth, pancreas and small intestine
lipase enzymes are produced in the pancreas and small intestine
protease enzymes are produced in the stomach, pancreas and small intestine
What is the total magnification of a light microscope with an eyepiece lens of ×10 and an objective lens of ×40?
10 × 40 = ×400
Total magnification of microscope = magnification of eyepiece lens × magnification of objective lens
How many orders of magnitude exist between an ant which is 3 mm long and a human hair which has a diameter of 100 μm? [3 mark]
Ant = 3 mm which is 0.003 m or 10−3 m
Human hair = 100 μm which is 0.0001 or 10−4 m
So there is one order of difference.
If a drawing of a cell in a textbook is 1 cm and the scale shows it to be 0.1 mm in real life, what is its magnification? [2 mark]
1 cm = 10 mm
So, 10 mm ÷ 0.1 mm = ×100
Compare and contrast diffusion and active transport
diffusion is the net movement of molecules from an area of high to lower concentration
active transport is the net movement of molecules from an area of low to higher concentration
diffusion is a passive process and does not require energy
active transport is an active process and so does require energy
diffusion occurs down a concentration gradient
active transport occurs up a concentration gradient
one mark for suitable example of diffusion, eg oxygen diffuses from the alveoli into the blood in the lungs
one mark for suitable example of active transport, eg plants use active transport to absorb nitrates from the soil
Describe how both the enzymes of the digestive system and its adaptations help break down foods. [5 marks]
carbohydrase enzymes break down carbohydrates into sugars
they are produced in the mouth, pancreas and small intestine
lipase enzymes break down fats and oils into fatty acids and glycerol
they are produced in the pancreas and small intestine
protease enzymes break down proteins into amino acids
they are produced in the stomach, pancreas and small intestine
the small intestine is about 4 metres long [1 mark] and has millions of tiny projections [1 mark] called villi [1 mark] which increase the surface area [1 mark] to increase diffusion [1 mark]
What is a section of DNA that codes for a protein called?
AGene
Describe the difference between genotypes and phenotypes? Give an example of each in your answer. [4 marks]
genotypes are letters used to determine characteristics
BB, Bb, bb for eye colour (accept other suitable examples)
phenotypes are physical descriptions using words that describe genotypes
so BB and Bb are brown eyes and bb is blue eyes (accept other suitable examples)
State what gamma rays, X-rays and ultraviolet rays are? [1 mark]
Types of ionising radiation
