1.1 Flashcards
Using units
1kilometre=
1m=
1cm=
1mm=
1um=
1kilometre= 1000metres (m)
1m= 100 centimetres (cm)
1cm=10milimetres (mm)
1mm=100micrometres (um)
1um=1000 nanometres (nm)
whats a light microscope
A microscope that uses visible light and lenses
What are the key features of a light microscope?
Stage, objective lens, eye piece lens, focus adjustment, light source
What is an electron microscope?
A microscope that uses electrons and electron lenses
What is magnification?
How many times bigger than it actually is
What is resolution?
Minimum distance apart that two objects can be in order for them to be seen as separate objects
What are the advantages of using an electron microscope compared to a light microscope?
Higher magnification and resolution
How is magnification calculated?
magnification = image size / actual size
Where are chromosomes found in an animal cell
nucleus
Describe the DNA in a bacteria cell
A single DNA loop or a DNA ring (plasmid)
what is the function of cytoplasm
the water-based gel in which organelles of all living cells are suspended
-where chemical reactions take place
whats the function of a cell membrane
-to control the passage of substances e.g glucose and mineral ions into the cell
-also controls the movement of substances e.g urea or hormones out the cell
whats the function of mitochondria
where aerobic respiration takes place, releasing energy for the cell
whats the function of ribosomes
where protein synthesis takes place
—making all the proteins needed in the cell
List the five parts of an animal cell
Nucleus, Cytoplasm, Cell membrane, Mitochondria, Ribosomes
List the three parts of a cell only found in plant cells
Vacuole (filled with cell sap), Chloroplasts, Cell wall
What is a cell wall made of in a plant cell?
cellulose
What function does cellulose have in a cell wall?
Provides strength
Name three specialised animal cells
Sperm, Nerve, Muscle
Name three specialised plant cells
Xylem, Root hair, Phloem
What is cell differentiation?
When different types of cells are formed in an organism
State two benefits of an electron microscope over a light microscope
Greater resolving power, Higher magnification
What is a stem cell?
An undifferentiated cell
What is diffusion?
Spreading out of particles of a substance in solution or a gas
What process moves substances into and out of a cell across a cell membrane?
Diffusion
What does diffusion result in?
The net movement of particles from an area of higher concentration to an area of lower concentration
Name two substances transported in and out of cells during gas exchange
Oxygen, Carbon Dioxide
Name three factors that affect diffusion
-Difference in concentration (concentration gradient),
-Temperature
-Surface area of membrane
How does water move across cell membranes?
by osmosis
What is osmosis?
Diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
What is active transport?
The movement of substances from a more dilute solution to a more concentrated solution
What’s the role of active transport in plants?
The absorption of mineral ions from dilute solutions in soil via root hairs
What’s the role of active transport in humans?
Allows sugar molecules to move from the gut into the blood
name two ways embryonic stem cells can cure diseases
-producing insulin
-replacing neurons
give the two main differences between active transport and diffusion
diffusion doesn’t require energy and AT does
-diffusion moves molecules from a high to low con AT goes low to high
