Topic 1a - Cells and Microscopy Flashcards
How do you convert between units?
…………..mm…..x10^-3
…………..µm……x10^-6……/1000
x1000…nm…….x10^-9
…………..pm…….x10^-12
What is a eukaryote?
An organism made up of eukaryotic cells
How do you calculate the total magnification?
Total magnification = eyepiece lens magnification x objective lens magnification
Labelled diagram of a bacteria cell
https://www.sheppardsoftware.com/science/cell/bacteria/game/
What is an organelle?
A tiny sub-cellular structure made up of different types of cells that perform a specific function within a cell
What is the function of a mitochondria?
Where most of the reactions for aerobic respiration takes place. Respiration releases energy that the cell needs to work.
Where are sperm cells and egg cells adapted to carry out their functions?
Sexual reproduction
Labelled diagram of a ciliated epithelial cell
Cilia (hair-like structures)
3 epithelial cells with a nucleus in each
Labelled sperm cell
https://www.educaplay.com/learning-resources/3046271-4_36_anatomy_of_sperm_cell.html
What is a prokaryote?
A prokaryotic cell (a single-celled organism)
What is the funtion of a cell wall?
A rigid structure made of cellulose. It supports and strengthens the cell
What is the function of a flagellum?
It rotates to make the bacterium move. Moves it away from harmful substances like toxins and towards beneficial things like nutrients and oxygen
What is a specialised cell?
A cell that performs a specific function
What are the characteristics of a light microscope?
- Used to study living cells
- Use light and lenses to form an image of a specimen and magnify it to make it look bigger
- Let us see individual cells and large subcellular structures like nuclei and chloroplasts
What are the rules for drawing an image?
- No Sketching
- Labels
- Magnification
- Draw exactly what you see
- Horizontal lines with no arrow heads
- No shading
- No frames around diagrams
- Fill the space (diagram ≥ 50% of space)
- Sharp pencil and ruler for labelling
- Title
What is the function of a ribosome?
Involved in protein synthesis (making proteins). The second stage of protein synthesis (translation) takes place here.
What is the function of a plasmid?
Contains genes for things like drug resistance, and can be passed between bacteria.
What is a chromosome?
Long, coiled up molecules of DNA - the genetic material of a cell.
What is the function of a cell membrane?
Holds the cell together and controls what goes in and out.
What are the rules for drawing and image?
- No sketching
- Labels
- Magnification
- Draw exactly what you see
- No shading
- Sharp pencil and rule for labelling
- Horizontal labels with no arrow heads
- Fill space (diagram ≥ 50% of space)
- No frames around diagrams
- Title
What is the function of a cell membrane?
Holds the cell together and controls what goes in and out
When were electron microscopes invented?
1930s
What are the characteristics of an electron microscope?
- Uses electrons instead of a light to form an image
- Higher magnification
- Higher resolution
- Can view living and non-living cells
- Lets us see smaller things in detail, like the internal structures of mitochondria and chloroplasts
What is resolution?
How clear and sharp an image is. A higher resolution would have a sharper, clearer image.
What is the function of an egg cell?
To carry female DNA and to nourish the developing embryo in the early stages
How do you observe a slide through a microscope?
1) Start by clipping the slide you prepared onto the stage
2) Select the lowest-powered objective lens (the one that produces the lowest magnification)
3) Use the coarse adjustment knob to move the stage up just below the objective lense
4) Adjust the focus with the fine 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 would like to observe the slide at a higher magnification, swap to a high-powered objective lens and refocus
What is a multicellular organism?
An organism that contains lots of different types of cells, where each type has a different function.
What is the function of a cytoplasm?
A gel-like substance where most of the chemical reactions happen. Contains enzymes that controls these chemical reactions
What is the function of a large vacuole?
Contains cell sap, a weak solution of sugar and salts. It maintains the internal pressure to support the cell.
How does a sperm cell transport male DNA to female DNA?
- It has a haploid nucleus, which contains half the amount of chromosomes
- Long tail to swim to the egg
- Lots of mitochondria in its middle section to provide energy needed to swim the distance
- Acrosome at the front stores enzymes the sperm needs to digest its way through the membrane of the egg cell
What is the function of a chloroplast?
Where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll, which absorbs the light needed for the photosynthesis.
When were light microscopes invented?
1590s
What do animal cells contain?
- Nucleus
- Cytoplasm
- Ribosome
- Cell membrane
- Mitochondria
What do eukaryotic and prokaryotic cells have various parts of?
- Subcellular structures
- Organelles
- Cytoplasm
- Ribosome
What is an example of a membrane bound organelle?
A nucleus
What is homeostasis?
Controlling internal conditions, such as temperature. It is constant within a narrow range.
What is magnification?
How much bigger the image is than the real object you’re looking at
What do bacteria cells contain?
- Chromosomal DNA
- Plasmid DNA
- Cell membrane
- Ribosome
- Flagella
How does and egg cell carry female DNA and nourish the embryo in the early stages?
- It has a haploid nucleus which contains half the amount of chromosomes in a normal body cell
- Contains nutrients in the cytoplasm to feed the embryo
- Straight after fertilisation, its membrane changes structure to stop any more sperm getting in. This makes the offspring end up with the right amount of DNA.
What is a haploid nucleus?
A nucleus that contains half the number of chromosomes that are in a normal body cell, e.g., a sperm cell has 23 chromosomes and an egg cell has 23 chromosomes, to make a human cell, which contains 46 chromosomes.
What is the function of a ciliated epithelial cell?
To move substances - the cilia beat to move substances in one direction, along the surface of the tissue
What is the function of sperm?
To transport the male DNA to the female DNA
What is the formula to calculate magnification?
magnification = image size ÷ actual size
What do plant cells contain?
- nucleus
- ribosomes
- cell wall
- cell membrane
- cytoplasm
- mitochondria
- vacuole
- chloroplasts
Give an example of a prokaryotic cell
Bacteria cell
Give an example of a eukaryotic cell
- Plant cell
- Animal cell
What is the function of the nucleus?
Contains genetic material which controls the activities of the cell. Genetic material is arranged into chromosomes.
How do you set up an onion cell slide?
1) Add a drop of water to the middle of a clean slide
2) Cut up an onion and separate it out into layers. Use tweezers to peel off some epidermal tissue from the bottom of one of the layers
3) Using tweezers, place the epidermal tissue onto the water on the slide
4) Add a drop of iodine solution onto the epidermal tissue. Iodine is used as a stain, which shows a clearer image through the microscope
5) Place the cover slip upright onto the slide. Carefully lower it, so that it covers the specimen. try not to get any air bubbles under there - they’ll obstruct any view of the specimen
Labelled diagram of an animal cell
https://wordwall.net/resource/24642715/animal-and-plant-cells
What is microscopy?
the study of very small objects, such as cells, using an instrument called a microscope
