Cell Biology. Flashcards
What are all things made from?
Cells.
What are the two types of cells?
Prokaryote and eukaryote.
Describe an eukayote cell.
Complex and include animal and plant cells.
Describe a prokaryote cell.
Smaller and simpler - Bacteria.
What is the scientific word for the different parts of a cell?
Subcellular structures.
Name the sub-celluar structures of an animal cell.
Nucleus Cytoplasm Ribosomes Cell Membrane Mitochondria
Define a nucleus.
Contains genetic material that controls the activities of the cell.
Define a cytoplasm.
gel like substance where most of the chemical reactions happen. It contains enzymes that control these reactions.
Define cell membrane.
Holds the cell together and controls what goes in and out.
Define mitochondria.
these are where most of the reactions for aerobic respiration takes place. Respiration transfers energy that the cell needs to work.
Define Ribosomes.
these are where the proteins are made in the cell.
Give the 3 subcellular structures of a plant cell.
Cell Wall Permananent Vacuole Chloroplasts
Define a cell wall of a plant.
Rigid cell wall made from cellulose it supports the cell and strenghtens it.
Define a permanent vacuole.
contains cell sap a weak solution of sugars and salts.
Define the chloroplasts of a plant.
where photosynthesis occurs which makes food for the plant. They contain a green substance called chlorophyll, which absorbs the light needed for photosynethesis.
What does a bacterial cell not have?
chloroplasts, mitochondria and don’t have a true nucleus instead they have a single circular strand of DNA that floats freely in the cytoplasm.
Sub-cellular structures of a bacteria.
Cell-membrane Cytoplasm Cell wall Plasmids-small rings of DNA. Circular strand of DNA thats floats freely in the cytoplasm.
What do microscopes allow us to do?
see things we can’t see with the naked eye. And microscopy techniques hae developed over the years as technology adn knowledge has improved.
What are light microscopes?
Use light and lenses to form and image of a specimen and magnify it. Let us see individual cells and large subcellular structures like nuclei.
What is an electron microscope?
use electrons to form an image.Thye have higher magnification and a higher resoloution (ability to distinguish between two points - a sharper image) you can see smaller things in more detail like the internal structure of a chloroplast and ribosomes and plasmids.
Formula for magnification?
image size / real size
Magnification of triangle.
Image size mag real size
How to prepare a slide to iew onion cells.
Add a drop of water to the middle of a clean slide. Cut up an onion and seperate it out into layers. Use tweezers to peel off some epidermal tissue from the bottom of one of the layers. Using tweezers place the epidermal tissue into the water on the slide. Add a drop of iodine soloution iodine solution is a stain stains are used to highlight objects in a cell by adding colour to them. Place a cover slip 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 as theyll ebstruct the view of the specimen.
How to look at your slide.
Clip the slide you have prepared onto the stage. Select the lowest powered objective lens Use the coarse adjustment knob to move the stage up to just below the objective lens. Look down at the eyepeice. use the coarse adjustment knob to move the stage downwards until the image is roughly in focus. Adjust the focus with the fine adjustment knob until you get a clear image of whats on the slide. If you need to see the slide with greater magnification swap to a higher powered objective lens and refocus.
How to draw your obserations from a microscope.
Draw what you see under the microscope using a pencil with a sharp point. Make sure drawing takes up at least half of the space and is drawn clearly with unbroken lines. Your drawing should not inculde any colour or shading. When drawing cells the subcellular structures should be drawn in proportion. Remember to include a title of what your’e observing and write down the magnification that it was observed under. Label the important features of your drawing using straight uncrossed lines.
What is differentiation?
process by which a cell changes to become specialsised for its job. As cells change they develop different subcellular structures and turn into different types of cells which allows them to carry out specific functions.
When does most differentation occur.
As an organism develops
When does differentiation occur in an animal cell?
Is lost at an early stage after they become specialised however lots of plants cells dont ever lose this ability.
What are differentiated cells in mature animals used for?
Repairing and replacing cells such as skin or blood cells.
What are differentiated cells called?
Stem cells.
Examples of specialised cells.
Sperm Cells Nerve Cells Muscle Cells Root hair cells Phloem and Xylem cells
What are sperm cells specialised for?
reproduction, the function of a sperm is to get male DNA to the female DNA.
How has sperm adapted?
It has a long tail and a streamlined head to help it swim to the egg. There are lots 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?
Rapid signalling.
How have nerve cells adapted?
the function of nerve cells are carrying electrical signals from on part of the body to another. These cells are long to cover more distance and have branched connections at their ends to connect to ther nerve cells and form a network throughout the body.
What are muscle cells specialised for?
contraction.
How have muscle cells adapted?
the function is to contract quickly. These cells are long so they have space to contract and contain lots of mitochondria to generate the enrgy needed for contraction.
What are root hair cells specialised for?
absorbing water and minerals.
How have root hair cells adapted?
root hair cells are on the surface of plant roots which grow into long hairs that stick out into the soil. This gives the plant a big surface area for absorbing water and mineral ions from the soil.
What are phloem and xylem cells specialised for?
transporting substances
How are phloem and xylem adapted?
Form phloem and xylem tubes which transport substances such as food and water around plants.
To form these tubes the cells are long and join at the ends.
Xylem cells are hollow in the cnetre and phloem have few subcellular sructures so stuff can flow through them
Where are chromosomes?
most cells in your body have a nucleus, the nucleus contains genetic material in the form of chromosomes.
What are chromosomes?
coiled up lenghts of DNA molecules
What does each chromosome carry?
large number of genes different genes control the development of different charachterisitics eg:hair colour
What do body cells have two copies of?
each chromosome one from the organisms mum and dad
so humans have two copies fo chromosome 1 chromosome 2 etc
How many pairs of chromosomes in a cell?
23
What is the cell cycle?
body cells in multicellular orgainsm divide to poduce new cells as part of a series of stages in the cell cycle
What is the stage of the cell cycle when the cell divides?
mitosis
