B1-cell structure Flashcards
what is a eukaryotic cell?
a eukaryotic cell is an animal or plant cell
they have genetic material that forms chromosomes and is contained in nucleus
function of cell membrane
controls the movement of substances in and out of the cell
function of nucleus
contains DNA
function of mitochondria
where is energy is released through respiration to transfer energy for a he cell
function of cytoplasm
where chemical reactions occur
function of ribosomes
site of protein synthesis-enable production of proteins
function of permanent vacuole
contains cell sap
function of chloroplasts
contains chlorophyll to absorb light energy for photosynthesis
function of cell wall
made of cellulose strengthening the cell
what is a prokaryotic cell?
simple cells that lack a nucleus and other membrane-bound organelles
and are single-celled
type of bacteria cell
why don’t prokaryotic cells have a nucleus-what’s the main genetic material in a prokaryotic cell?
as they have a single loop of DNA
and also small rings of DNA called plasmids
equation for magnification
magnification=image size/actual size
What type of cell are bacteria
Prokaryotic
Where is the dna found in eukaryotic cells
nucleus
How are electron microscopes different to light microscopes
Electron microscopes use beams of electrons instead of light, cannot be used to view living samples, are much more expensive, and have a much higher magnification and resolution
Function of a red blood cells
Carries oxygen around the body
3 adaptations of a red blood cell
No nucleus
Contains a red pigment (haemoglobin)
Has a bi-concave disc shape
Function of a nerve cell
Cherries electrical impulses around the body
Two adaptations of a nerve cell
Branched endings
Myelin sheath insulates the axon
Function of a sperm cell
Fertilise an ovum (egg)
Two adaptations of a sperm cell
Flagellum (tail)
contains a lot of mitochondria
Function of a palisade cell
Carries out photosynthesis in a leaf
Two adaptations of a palisade cell
Lots of chloroplast
located at the top surface of leaf
Function of a root hair cell
Absorbs minerals and water from the soil
Two adaptations of a root hair cell
Long projection
Lots of mitochondria
How do you determine the actual size of a cell using magnification
1.Step one determine the magnification
Total magnification = objective lens magnification x eyepiece lens magnification
2. step two put the numbers into the equation
magnification =size of image / actual size of object
3. step three rearrange
4. step four convert to standard form
To know…
Describe how a microscope should be set up
Label a microscope
Describe how to focus on a slide containing specimen
Make a labeled scientific drawing of what you observe
explain where in the plant a cell could be found
Leaf/stem-as it contains chloroplast
Why is methylene (blue dye) added to a cell sample
To make nucleus more visible
To observe the cell in greater detail you could…
Use a higher-power objective lens
What is a tissue
A group of cells with similar structures working together to perform a function
What does xylem tissue do
Transports water and mineral ions around the plants
How are the xylem tubes formed
Lignin builds up in the cell walls
Cells die
Forming long hollow tubes
2 ways xylem tissue is adapted to its function
Long hollow tubes to allow water/minerals to move easily around the plant
Lignin makes cells strong therefore it can withstand pressure of moving water and helps supports plants stem
Name another plant transport tissue
Phloem
1 difference between cell wall of plant cell and cell wall of bacterial cell
Plant-contain glucose
Bacteria-contain peptidoglycan
Which feature needs to be present on a bacterial cell if it needs to move in water of liquid
Flagellum
What is a specialised cell
A cell that is adapted to perform a particular function
What is diffusion?
A net movement of particles from an area of high concentration area low concentration along a concentration gradient. This is a passive process meaning it does not require energy from respiration.
Name three factors that affect the rate of diffusion
Concentration gradient
Temperature
Membrane surface area
What process is diffusion
Passive-no energy required
Where does diffusion happen in humans
Nutrients in the small intestine diffuse into the blood in the capillaries throughout the villi
Oxygen diffuses from the air in the alveoli into the blood in the capillaries
Where does diffusion happen in fish
Oxygen from water passing over the gills diffuses into the blood in the gill filaments
Where does diffusion happen in plants
Carbon dioxide used for photosynthesis diffuses into leaves through the stomata
What is osmosis
Diffusion of water from a dilute solution to a concentrated solution to a particularly permeable membrane -water moves from an area of low solute concentration to an area of height solute concentration
What process is osmosis
Passive
Where in plants does osmosis take place
Water moves by osmosis from a dilute solution in the soil to a concentrated solution the root hair cell
What is active transport
The movement of particles from a more dilute solution to a more concentrated solution using energy from respiration-particles move against the concentration gradient from low to high
What process is active transport
Active?
Uses energy released during respiration
Where in humans does active transport take place
It allows sugar molecules to be absorbed from the small intestine when the sugar concentration is higher in the blood than in the small intestine
Where is plants is active transport used
To absorb the mineral ions into the root hair cells from more dilute solutions in the soil
If the concentration is steeper it means…
The faster the rate of diffusion is
The higher the temp…
The faster the rate of diffusion
The larger the membrane surface area is…
The faster the rate of diffusion
Single celled organisms have a l.s.a to volume ratio
Why
To allow enough molecules to be transported across their membranes to meet their needs
Multicellular organisms have a small s.a to volume ratio
This means they need specialised organs systems and cells to allow enough molecules to be transported into and out of their cells
Billow in the small intestine used for
Absorbing nutrients
Alveoli in lungs for
Gas exchange
Fish gills for
Gas exchange
Root hair cells for
Uptake of water and minerals
