B1 Cell Structure And Transport Flashcards
What is the function of the nucleus?
Controls all the activities of the cell and is surrounded by nuclear memebrane. Contains DNA
What is the function of the cytoplasm?
A liquid gel which contains organelles and where most chemical reactions take place
What is the function of the cell membrane?
Controls what enters and leaves the cell such as glucose and mineral ions
What is the function of mitochondria
Structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell.
What is the function of ribosomes?
Where protein synthesis takes place, maing all proteins needed in the cell.
What is the function of a cell wall
Rigid,made of cellulose. It supports the cell and strengthens it
What is the function of the permanent vacuole?
Contains cell sap, a week solution of suger and salts
What is the function of chloroplasts?
Where photosynthesis occurs,which makes food for the plant. They contain a green substance called chlorophyll, which absorbs the light needed for photosynethis
What is a prokaryotic cell and give examples.
Cells are small and simple eg bacteria cells
What is an eukaryotic cell and give examples.
They are complex cells, eg plant and animal cells
What are microscopes?
Microscopes let us see things that we can’t see with the naked eye. The microscopy techniques
we can use have developed over the years as technology and knowledge have improved.
What is a light microscope?
Light microscopes use light and lenses to form an image of a specimen and magnily it (make it look bigger). They let us see individual cells and large subcelluler structures, like nuclei.
What is an electron microscope
Electron microscopes use electrons instead of light to form an image.
They have a much higher magnification than light
They also have a higher resolution. (Resolution is the ability to distinguish between two points, so a higher recolution gives a sharper inage.)
Electron microscopes let us see much smaller things in more detail, like the internal structure of mitochondria and chloroplast .They even let us see tinier things like ribosomes and plasnids.
What is the formula for magnification?
Magnification = image size/real size
What is the formula for image size?
Image size = magnification X real size
What is the formula for real size?
Real size = image size/magnification
How to prepare your slide. (Required practical)
If you want to look at a specimen (e.g, plant or animal cells) under a light microscope, you need to put it on a microscope slide first. A slide is a strip of clear glass or plastic onto which the specimen is mounted.
Here’s how to prepare a slide to view onion cells:
1) Add a drop of water to the middle of a clean slide.
Water drop mixed with sodine
2) Cut up an onion and separate it ouf into layers. Use tweezers to peel off
Cover slip
some spidermal tissue from the bottom of one of the layers.
3) Using the freezers, place the epidermal tissue into the water on the slide.
4) Add a drop of lodice solution. lodine solution is a stain Specimen stained with iodine Slide Stains are used to highlight objects in a cell by adding colour to them.
5) Place a cover slip (a square of thin, transparent plastic on glass) on top. To do this, stand the cover slip upright on the slide, next to the water droplet. Then carefully tilt and lower it so it covers the specimen.
Try not to get any air bubbles under there — they’ll obstruct your view of the specimen.
How to prepare a light microscope
1) Clip the slide you’ve prepared onto the stage.
2) Select the lowest-powered objective lens (ie. the one that produces the lowest magnification).
3) Use the coarse adjustment knob to move the stage up to just below the objective lens.
4) Look down the eyepiece. Use the coarse adjustment knob to move the stage downwards until the image is roughly in focus.
5) Adjust the focus with the fine adjustment knob, until you get a clear image of what’s on the slide.
6) If you need to see the slide with greater magnification, swap to a higher-powered objective lens and refocus.
What is differentiation?
Its the process by which a cell changes to become specialised for its job
What are sperm specialised for?
SPERM CELLS are specialised for REPRODUCTION
The function of a sperm is basically to get the male DNA to the female DNA.
It has a long tail and a streamlined head to help it swim to the egg
There are a lot of mitochondria in the cell to provide the energy needed.
It also carries enzymes in its head to digest through the egg cell membrane.
What are nerve cells specialised for?
NERVE CELLS are specialised for RAPID SIGNALLING
The function of nerve cells is to carry electrical signals from one part of the body to another. These cells are long (to cover more distance) and have branched connections at their ends to connect to other nerve cells and form a network throughout the body.
What are muscle cells specialised for?
MUSCLE CELLS are specialised for CONTRACTION
The function of a muscle cell is to contract quickly. These cells are long (so that they have space to contract) and contain lots of mitochondria to generate the energy needed for contraction.
What are root hair cells specialised for?
ROOT HAIR CELLS are specialised for absorbing WATER and MINERALS
Root hair cells are cells on the surface of plant roots, which grow into long “hairs” that stick out into the soil. This gives the plant a big surface aren for absorbing water and mineral ions from the soil.
What are phloem and xylem cells specialised for?
PHLOEM and XYLEM CELLS are specialised for TRANSPORTING SUBSTANCES
Phloem and xylem ceslls form phloem and xylem tubes, which transport subatances such as food and water around plants. To form the tubes, the cells are long and joined end to end. Xylem cells are hollow in the centre and phloem cells have very few subcellular structures, so that stuff can flow through them.
What is diffusion?
Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration,down a concentration gradient until an equilibrium is reached.
What is osmosis?
The diffusion of water from a dilute solution to a concentrated solution a partially permeable membrane. (High concentration to low concentration)
