B1 Cell structure and transport Flashcards
How do Light Microscopes work?
Beam a light around an object
How far can they magnify
around 2000x
Benefits of a light microscope
cheap,can be used anywhere and can magnify live specimens
How do electron microscopes work
They use a beam of electrons to form an image
How far can they magnify
2 000 000x
Difference between transition and scanning electron microscopes.
Transition takes 2d images at high resolution and high magnification
Scanning take 3d images but at lower magnification
Disadvantages of electron microscope
Large,very expensive, have to be kept in special temperature pressure and humidity
Magnification of a light microscope
Eyepiece lens magnification x Objective lens magnification
The formula to calculate the size of an object
size of real object= size of image/magnification
What is resolution
the shortest distance between two points on a specimen that can still be seen as two different points by the observer
Resolving power of Light and electron microscope
Light microscope- 200nm
A scanning electron -10 nm
a transition - 0.2nm
What do the nucleus of an animal cell do
controls all the activities of the cell and contains the genes for chromosomes that carry the instruction for making the proteins needed to build new cells.In a diagram it is repecented by the biggest circle within the cell
What does the cytoplasm do in an animal cell
the gel in the cell where most chemical reactions happen. In a diagram it is represented as the interior backround inside the cell.
What is the cell membrane do in a animal cell
Controls the passage of substances such as glucose and mineral ions into the cells and substances like hormones out of the cell.In a diagram it is represented as the wall outside of the cell.
What does the mitochondria do in a animal cell
Aerobic respiration takes place in here releasing energy for the cell.They are either represented as small dots or ovals in the diagram
What do ribosomes
protein synthesis happens here making all the proteins needed for the cell.Either represented as small dots near the stringy material which is the endoplasmic reticulum in the cell diagram.
How are plants different from animals.
They do not move and they make food from themselves in a process called photosynthesis
What is the cell wall in the plant cell
They are made of cellulose that streghthens the cell and gives it support. Represented as the thick wall outside the cell membrane.
What do chloroplasts do in a plant cell
They contain the green substances chlorophyll which makes the green and absorbs light so the plant make energy via photosynthesis.They are found on cells above ground because the light is not found undergriund.They look like green mitochondria
What does the permament vacuole do in a plant cell
It is a space in the cytoplasm filled with cell sap and this is important for keeping the cells rigid to support the plants
What are plants and animals both examples of and what does this mean
Animal and plant are both eukaryotes along with fungi and protists which means they all have nucleus that produces the genetic code (DNA)
Bacteria are
single celled organism and an example of prokaryotes along with archaea
How small do bacteria get
0.2 to 2.0 micrometres
What do Prokaryotic cell contain sometimes
Extra small rings of DNA called Plasmids which code for specific features
What do they have instead of a nucleus
Genetic material in a loop
What are the two specific features that some bacterial cells have
A slime capsule that is protective and a flagella which moves them around
What do cells do as a organism develops
differentiate to form different types of specialised cells
What are Nerve cells specialised to do
Carry electrical impulses to provide a rapid communication system between different parts of the body
What are the nerve cells adaptations
lots of dendrites to make connections with other cells
a long axon to carry the nerve impulse from one place to another
the synapses are adapted to pass the impulses to another cell or a muscle using special transmitter chemicals and they have lots of mitochondria to help make the chemicals
Muscle cells are specialised in what way
They can contract and relax
What do striated muscles cells do
move different parts of the body
Adaptations of Striated muscle cells
-They contain special proteins that slide making the fibres contract
-Contain many mitochondria to transfer the energy needed for the chemical reactions that take place as the cells contract
-Stores glycogen which can be used by the mitochondria as energy
Adaptations of sperm cells
-Tails to move to the egg
-The middlesection has mitochondria to provide energy to the tail
-The achrosome has enzymes to break the egg
-the nucleus has the genetic information
What are root hair cells
Cells in the root that takes in water and mineral ions and is close to the xylem so the rest of the plants can have these so photosynthesis can occur
adaptations of root hair cells
bigger surface area to take in more water
large vacuole that speeds up water to speed up the movement of water by osmosis
many mitochondria to provide energy for the active tansport of minerals ions
photosynthetic cells adaptations
Have chloroplasts to trap light for photosynthesis
-Positioned in continuous layers in the leabes and outer layers so they absorb as much light as possible
-They have a large permament vacuole that helps the cell rigid and helps the leaf spread out so iit can capture as much light as possible
What is the xylem cell
the xylem is the transport tissue in plants that carries water and minera;s opms from the roots to the rest of the plant
adaptations of the xylem cell
cells are alive but dies and form long hollow tubes that allow water and mineral ions
to easily move through them
-spirals of lignin in the xylem cells make them very strong.
adaptations of phloem cells
phloem is specialised transport tissue that carries the food made by photosynthesis around the body of the plant
-the cell wall betweens the cells break down to form special sieve plates these allow water carrying the food to move freely op and down the tubes to where it is needed
-phloem cells lose a lot of their internal structures but they are supoorted by companion cells that keep them alive.
What is one way substances like glucose and oxygen move in and out of the cell
diffusion-moving from area of high concentration to a lower concentration, it takes place because the random movement of particles bump around until they are in a random concentration
