Topic 1- Cell Biology Flashcards
difference between prokaryotic cell and a eukaryotic cell? 4
prokaryotic cell has no nucleus
Prokaryote is simpler/ smaller
eukaryotic, nucleus with genetic material
Magnification equation
Image size/actual size
What do both plant and animal have (5)
nucleus cytoplasm cell membrane mitochondria ribosomes
What is additional in plant cell (3)
chloroplasts
permanent vacuole
cell wall
What is a plasmid?2
a circular strand of DNA that floats freely in the cytoplasm
Carry genes that provide genetic advantages
e.g. antibiotic resistance.
Nucleus function 2
genetic material
control cellular activities
Structure and function of cyptolasm 3
fluid of the cell contains enzymes and nutrients
Chemical reactions take place transport medium
Site of cellular reactions e.g. first stage of respiration
Function of cell membrane 1
controls what goes in and out of the cell
Function of mitchondria2
Site of later stages of aerobic respiration in which ATP is produced.
Function of ribosomes
Joins amino acids in a specific order for protein synthesis
function and Vacuole contains 3
contains cell sap
supports cell,
maintaining turgidity
cell wall function 3
made of cellulose
strengthens the cell
Prevents the cell bursting when water enters by osmosis.
chloroplasts function 2
where photosynthesis occurs. they make the food for the plant
Sperm cells adapted and function 4
Haploid nucleus contains genetic information
streamlined head and long tail (swim to egg)
mitochondria provide energy needed for tail movement
Acrosome contains enzymes that digest the egg cell membrane.
Muscle cells adapted and function 2
contraction- long so they have space to contract
Mitochondria to provide energy for muscle contraction.
Root hair cell function and adaption 2
absorbing water and minerals- big surface area
Large surface area to absorb nutrients and water from surrounding soil.
● Thin walls that do not restrict water absorption.
Nerve cells adapted and function 2
rapid signalling- long, branched connections
Long axon allows electrical impulses to be transmitted all over the body from the central nervous system.
Xylem adaptations and function 3
transporting water
Thick woody side walls- strengthen structure prevent collapse
long, hollow- route for water to flow
Phloem adaptations and function 4
transport food
- sieve plates- dissolved sugars/ amino acids transported up and down
- companion cells provide energy for active transport
Importance of cell differentiation
a process where cells become specialized specific to function in the body
Allows production of different tissues and
organs that perform various vital functions in the human body.
what is the purpose of cell division in mature animals
repair and replacement of cells
differences between electron and light microscope 3
- electron microscope has higher magnification and resolution
- beam of light, beam of electrons
- electrons have shorter wave length=higher resolution
how electron microscopy has increased understanding of sub-cellular structures 2
used to study cells in much finer detail enabled to see and understand many more sub-cellular structures
Enable scientists to develop more accurate explanations about how cell structure relates to function
define resolution
smallest distance between two objects that can be distinguished
how do bacteria multiply
binary fission
2 ways bacteria can be grown
nutrient broth solution
colonies in a agar gel plate
What is diffusion?
movement of particles from an
area of higher concentration to an area of lower concentration.
three main factors affect the rate of
diffusion?
Concentration gradient - larger gradient, faster
diffusion.
Temperature - higher temperature, faster diffusion
Surface area - larger surface area, faster diffusion.
substances transported by diffusion in
the lungs and the kidney 2
Lungs:
oxygen diffuses into blood from the lungs
carbon dioxide diffuses into the lungs from the blood, both down their concentration gradient.
Kidney:
urea diffuses from cells into blood plasma so it can be excreted in urine
How are single-celled organisms adapted for diffusion?
have a large surface area to volume
ratio maximises the rate of diffusion of
molecules to meet the organism’s needs
What four factors increase the effectiveness of a gas exchange surface? 4
Large surface area
Thin membrane (short diffusion path)
Efficient blood supply (animals)
Ventilation (animals)
What is osmosis?
The movement of water from a dilute solution to a concentrated solution through a partially permeable membrane
diffusion of water from a dilute solution to a concentrated solution
through a partially permeable membrane.
What is meant when a solution is isotonic and hypertonic, hypotonic to a cell?3
iso-concentration of sugar in the external solution is the same as the internal
hyper-concentration of sugar in external solution is higher then the internal
hypo-concentration of sugar in external is lower than the internal
What may happen when an animal cell is placed in a very hypotonic solution?
Water moves into the cell, causing it to burst
What may happen when an animal cell is placed in a very hypertonic solution?
Water moves out of the cell, causing it to shrivel up
Osmosis in plants 3
If the external solution is more dilute, water will move into the cell and into the
vacuole, causing it to swell,
causing turgor keeping
the leaves and stems of plants rigid).
if the external solution is less dilute, water will move out of the cell and they will
become soft. Eventually the cell membrane will move away from the cell wall (called
plasmolysis) and it will die.
What is active transport?2
movement of molecules from a more
dilute solution to a more concentrated solution
against a concentration gradient, using energy from respiration.
How do plant root hair cells use active transport2
take up mineral ions from a more dilute solution in soils.
Ions magnesium and nitrates
are required for healthy growth
How is active transport used to absorb the
products of digestion?2
to transport glucose from a lower concentration in the gut to a higher
concentration in the blood.
Glucose is then
transported to the tissues where it can be used in respiration
How is genetic information stored in a prokaryotic
cell?3
Found free within the cytoplasm as:
● Chromosomal DNA (single large loop of circular DNA)
● Plasmid DNA
At what point in their life cycle do most animal cells
differentiate?
Early in their life cycle
For how long do plant cells retain the ability to differentiate?
Throughout their entire life cycle
What are the advantages of light microscopes? (4)
● Inexpensive
● Easy to use
● Portable
● Observe both dead and living specimens
Name the two types of electron microscope
Transmission electron microscope (TEM)
Scanning electron microscope (SEM)
What is the advantage of electron
microscopes?
Greater magnification and resolution.
Why do electron microscopes have a greater
magnification and resolution?
They use a beam of electrons which has
a shorter wavelength than photons of
light.
What are the disadvantages of electron
microscopes? (4)
● Expensive
● Large so less portable
● Require training to use
● Only dead specimens can be observed
How do plant leaves and stems remain rigid?
Turgor pressure - water moves in by osmosis, causing the vacuole to swell and the cytoplasm to press against the cell wall.
What may happen when a plant cell is placed in a very hypertonic solution?
Water moves out of the cell by osmosis and the vacuole and cytoplasm decrease in size. The cell membrane may pull away from the cell wall, causing the cell to become plasmolysed.
