1) Cell Structures & Processes Flashcards
What are the types of cell?
The 2 types of cell are: Eukaryotic cells
Prokaryotic cells
Where are eukaryotic cells found?
Plants
Animals
Fungi
Protists
What are protists?
Protists are single celled organisms that don’t fit into other categories
How big are eukaryotic cells?
10 - 100 micrometres (μm)
Where are prokaryotic cells found?
Bacteria
How big are prokaryotic cells?
0.5 - 5.0 micrometres (μm)
What are features of prokaryotic cells?
No mitochondira or chloroplasts
Single DNA loop in cytoplasm
Plasmids (small sings of DNA)
What do animal cells contain?
Cell membrane Nucleus Mitochondria Ribosomes Cytoplasm
What does the cell membrane do?
The cell membrane separates the interior of the cell from the environment. It is selectively permeable
What does the nucleus do?
It is the control centre of the cell, it contains chromosomes
What do ribosomes do?
Ribosomes are responsible for synthesising proteins
What do mitchondria do?
Mitochondria produce energy, aerobic respiration releases energy in the mitochondria
What does the cytoplasm do?
The cytoplasm is a jelly-like fluid where most chemical reactions occur
What additional sub-cellular structures do plant cells have?
Permanent vacuole
Chloroplasts
Cell wall
What does the permament vacuole do?
The permanent vacuole is a fluid-filled sac storing water, it is enclosed in a membrane and can make up 90% of a plant cell’s volume
What do chloroplasts do?
Choroplasts contain chlorophyll which is needed for photosynthesis
What does the cell wall do?
The cell wall surrounds the cell and increases the structural strength of the cell
What is the cell wall made of?
Cellulose makes up cell walls
What sub-cellular structures are found inside bacteria?
Ribosomes Flagella Cell Wall Cell Membrane Plasmids Cytoplasm
What is a flagella?
A flagella is a whip-like structure for bacteria’s movement
What are plasmids?
Plasmids are small rings of DNA
What does a sperm cell’s head contain?
The head contains the nucelus, carrying one half of an organism’s genetic material
What does a sperm cell’s middle section contain
Lots of mitchondria to provide energy to reach the egg
What is an acrosome?
Found at the tip of a sperm cell’s head an acrosome contains a digestive enzyme needed to penetrate an egg cell
What does a fertilised egg cell become?
A zygote
How is an egg’s membrane adapted?
It changes structure once the egg is fertilised so no more sperm can enter
How much genetic information does a haploid nucleus contain?
A haploid nucleus contains half of the genetic material needed for a new zygote (23 chromosomes)
What is an egg cell packed with?
Lots of cytoplasms which is packed with nutrients for the zygote to grow
What do cilliated epithelia cells do?
Waft mucus to the back of the throat to be swallowed
What are features of cilliated epithelial cells?
Cilia- hair like structures which can move in unison
Mitochondria- moving cilia needs energy from respiration
What is resolution?
The ability to distinguish between two or more objects close together
What does magnification tell us?
How many times larger and image seen through a microscope is compared to the real object
How big is a millimetre in standard form?
1 millimetre = 1x10^-3 m
How big is a micrometre in standard form?
1 micrometre = 1x10^-6 m
How big is a nanometre in standard form?
1 nanometre = 1x10^-9 m
What did the light microscope discover?
Bacteria
What did electron miscopes discover?
Sub-cellular structures
How structures function
How is a light microscope experiment conducted?
1) Thin tissue sample on microscope slide
2) Add drops of suitable dye
3) Place coverslip over and slide on microscope stage
4) Use objective lens with lowest magnification to focus
5) Increase magnification and refocus to see different cell features
How do you multiply in standard form?
Multiply the leading numbers
Add the powers
Change to correct format
How big is a kilometre in standard form?
1 kilometre = 1x10^3 m
How big is a centimetre in standard form?
1 centimetre = 1x10^-2 m
How big is a picometre in standard form?
1 picometre = 1x10^-12 m
Rank the units for size
Kilometre (km) Metre (m) Centimetre (cm) Millimetre (mm) Micrometre (μm) Nanometre (nm) Picometre (pm)
What bind’s to an enzyme’s active site?
The reacting chemical (substrate)
How many enzymes are there for every substrate?
Usually one
What do enzymes do?
Catalyse reactions in the body
How does temperature affect the rate of enzyme action?
Increasing temperature initally increases rate, after enzyme’s optimum temperature rate decreases
When does a denatured enzyme mean?
The active site has changed shape (loses it catalytic ability) due to high temperatures or pH
How does pH affect the rate of enzymes action?
Each enzyme has an optimum pH and moving away from it deceases rate. Too high or low pH causes the enzyme to denature
How does substrate concentration affect the rate of enzymes action?
Increasing substrate concentration increases rate until a point where it plateaus
How is reaction rate calculated?
reaction rate = change in mass / change in time
How do we measure the effect of pH on amylase?
1) Add amylase to starch solution
2) Every 30 seconds take a drop of the mixture and add a drop of iodine solution
3) Record the total time taken for iodine to stop turning blue
How do we find amylase’s optimal pH?
Repeat the starch experiment using different pH starch solutions, shorter the time taken for iodine to stop changing colour, closer to optimum pH
What enzyme breaks down starch?
Amylase breaks down starch
Where are digestive enzymes produced?
Glands and the lining of the gut
What are digestive enzymes used to do?
Breakdown large food molecules by catalysing insoluble food molecules into soluble molecules that can be absorbed by the bloodstream
What are the main digestive enzymes?
Amylase
Protease
Lipase
What does amylase break starch into?
Maltose
Amylase: Starch –> maltose (+other sugars)
Where are amylase action sites?
Small intestine
Mouth
Where is amylase produced?
Small intestine
Pancreas
Salivary Glands
What does protease break proteins into?
Amino acids
Protease: Protein –> amino acids
Where are protease action sites?
Small intestine
Stomach
Where is protease produced?
Small intestine
Stomach
Pancreas
What does lipase break lipids into?
Glycerol and Fatty acids
Lipase: Lipids –> Glycerol + Fatty acids
Where is lipase produced?
Small intestine
Pancreas
What is the test for proteins?
Biuret solution
Purple if proteins present
What is the test for starch?
Iodine solution
Blue-black if starch present
What is the test for sugar?
Benedict’s reagent and heat for 2 minutes
Green, yellow, or red if sugar present
What is the test for calory content in foods?
Burn a known mass of food under a boiling tube filled with a known volume of water, calculate chaneg in water temperature
What is the test for lipids?
Ethanol + water and shake
White emulsion if lipids present
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration
What particles are moved by diffusion?
Gases
Liquids
What factors affect diffusion?
Membrane surface area
Concentration gradient
Temperatur
How does temperature affect rate of diffusion?
Higher temperature = faster rate of diffusion
What is osmosis?
Diffusion of water across a partially permeable membrane
What is a partially permeable membrane?
Allows water through but not large molecules dissolved in water
How is osmosis investigated?
Cut discs in potato and measure mass
Put discs in different concentrations of sugar or salt solution
After 30 mins, measure mass of each disc
How is percentage change is mass calculated?
(Final mass - initial mass) / initial mass x 100 = percentage change
What is an independent variable?
A variable you can control
What is a dependent variable?
Measured as an outcome of the experiment
What is active transport?
The net movement of particles against the concentration gradient
What is required for active transport?
Energy
What is active transport used for in plants?
Mineral absorbtion in root hair cells
What is active transport used for in the gut?
Allows sugar molecules to be absorbed into the blood
