P1 - Cells Flashcards
Revise cells and cell processes
What are eukaryotic cells ?
Eukaryotic cells are complex, all animal and plant cells are eukaryotic.
What are prokaryotic cells ?
Prokaryotic cells are smaller and simpler, bacteria are prokaryotic cells.
What sub-cellular structures are in an animal cell ?
The nucleus, cytoplasm, cell membrane, mitochondria and ribosomes.
what sub-cellular structures do plant cells have that animal cells don’t ?
The cell wall, permanent vacuole and chloroplasts.
What sub-cellular structures do bacteria have ?
The cell wall, cell membrane, cytoplasm, a single loop of DNA (bacteria don’t have a true nucleus) and plasmids.
What are the two kinds of microscope ?
Light microscope and electron microscope.
What is the difference between light and electron microscopes ?
Electron microscopes have a higher resolution and magnification.
What is the formula to work out magnification ?
magnification = image size ÷ real size
How do you prepare a slide for a microscope ?
Add drop of water to the middle, use tweezers to place object into the water, add a drop of iodine solution to stain it and place a cover slip on top.
How do you use a light microscope ?
Clip the slide onto the stage, select objective lens with lowest magnification, use coarse adjustment knob to move stage up to just below objective lens, look through eyepiece and move stage downwards until roughly in focus, move fine adjustment knob until you get a clear image. For a bigger image use an objective lens with a higher magnification.
What are specialised cells ?
Cells in an organism that carry out a specific function.
What happens when cells differentiate ?
They develop different sub-cellular structures, they turn into different types of cells allowing them to carry out specific functions.
When can cells differentiate in animals ?
Only in the early stages of an animals life.
When can cells differentiate in plants ?
Lots of plants cells can for the whole of the plants life.
How are sperm cells specialised ?
They have tails and streamlined head to help them swim to the egg and has lots of mitochondria to provide energy for swimming. Also has enzymes in head to digest through egg cell membrane.
How are nerve cells specialised ?
They are long to cover more distance in the body and have branches at the end to connect to other nerve cells.
How are muscle cells specialised ?
They are long so they have space to contract and they have lots of mitochondria to provide energy for contracting.
How are root hair cells specialised ?
They grow long to stick into the ground, giving the plant a big surface area for absorbing water and mineral ions.
What does a phloem cell do ?
Transport food in a plant.
What does a xylem cell do ?
Transport water in a plant.
How are phloem and xylem cells specialised ?
The cells form tubes and are very long and joined end to end. Xylem cells are hollow and phloem cells have very few sub-cellular structures to allow lots of space inside for stuff to flow through them.
Where a chromosomes found ?
In the nucleus of a cell.
What are chromosomes ?
Coiled up lengths of DNA molecules, each one carries a large number of genes and different genes control the development of different characteristics.