B1 - Cell Structure And Tranport Flashcards
What are the basic units of measurement related to microscopy?
1 kilometre (km) = 1000 metres (m), 1 m = 100 centimetres (cm), 1 cm = 10 millimetres (mm), 1 mm = 1000 micrometres (µm), 1 µm = 1000 nanometres (nm)
A nanometre is 0.000 000 001 metres (or written in standard form as 1 × 10^-9 m)
What is the maximum magnification of a light microscope?
Around 2000 times (x2000)
School microscopes usually only magnify several hundred times.
When were the first light microscopes developed?
In the mid-17th century
What is the primary function of a light microscope?
To use a beam of light to form an image of an object
What are the types of electron microscopes and their features?
Transmission electron microscopes (2D images, high magnification and resolution), Scanning electron microscopes (3D images, lower magnifications)
Electron microscopes can magnify objects up to around 2000000 times.
What is a key disadvantage of electron microscopes?
They are large, very expensive, and require special controlled environments
How do you calculate the overall magnification of a microscope?
Multiply the magnification of the eyepiece lens by the magnification of the objective lens
If the eyepiece lens is x4 and the objective lens is x10, what is the overall magnification?
x40
What is the formula to calculate the size of an object under a microscope?
Size of image = magnification × size of real object
What does resolution in microscopy refer to?
The ability to distinguish between two objects that are close together
What is the resolving power of the best light microscopes?
About 200 nm
What is the significance of the magnification triangle in microscopy?
It helps to calculate the size of an object based on the image size and magnification
True or False: Light microscopes can only view dead specimens.
False
Light microscopes can magnify live specimens.
Fill in the blank: The first light microscopes were developed in the ______ century.
17th
What is the resolution between a light microscope and an electron microscope?
The resolution of an electron microscope is significantly higher than that of a light microscope.
How do you calculate the magnification of a specimen?
Magnification can be calculated using the formula Icm = 10n.
What is the equivalent of 1 mm in micrometers?
1 mm = 10 micrometers.
What is the equivalent of 1 picometer in meters?
1 pm = 10^-12 meters.
What parts are included in a light microscope?
- Eyepiece
- Coarse focus
- Objective lens
- Stage
- Fine focus
- Slide
- Light
True or False: A light microscope can be used to observe live specimens.
True
Fill in the blank: The formula to calculate real size is _______.
Icm = 10n
What is the purpose of the coarse focus on a microscope?
To bring the specimen into general focus.
What is the function of the objective lens in a microscope?
To magnify the specimen.
Fill in the blank: The _______ holds the slide in place on the stage.
stage clips
What is the resolution between a light microscope and an electron microscope?
The resolution of an electron microscope is significantly higher than that of a light microscope.
How do you calculate the magnification of a specimen?
Magnification can be calculated using the formula Icm = 10n.
What is the equivalent of 1 mm in micrometers?
1 mm = 10 micrometers.
What is the equivalent of 1 picometer in meters?
1 pm = 10^-12 meters.
What parts are included in a light microscope?
- Eyepiece
- Coarse focus
- Objective lens
- Stage
- Fine focus
- Slide
- Light
True or False: A light microscope can be used to observe live specimens.
True
Fill in the blank: The formula to calculate real size is _______.
Icm = 10n
What is the purpose of the coarse focus on a microscope?
To bring the specimen into general focus.
What is the function of the objective lens in a microscope?
To magnify the specimen.
Fill in the blank: The _______ holds the slide in place on the stage.
stage clips
What is the formula to calculate the size of an object under a microscope?
magnification = size of image / size of real object
If the magnification is X40 and the size of the image is 1 mm, what is the size of the real object?
size of real object = size of image / magnification = 1 mm / 40 = 0.025 mm or 25 um
What is the magnified height of an average person using one of the best light microscopes?
about 3.5 km
What is the magnified height of an average person using an electron microscope?
about 3500 km
What is the resolving power of a light microscope?
about 200 nm
What is the resolving power of a scanning electron microscope?
about 10 nm
What is the resolving power of a transmission electron microscope?
about 0.2 nm
True or False: If two objects are closer than a certain distance, they will appear as one object.
True
Fill in the blank: The distance apart of two atoms in a solid substance is approximately _______.
0.2 nm
What is resolving power
The ability to distinguish between two separate points.
What is the average length of an animal cell?
10-30 µm
An average animal cell would take 100,000-300,000 cells to line up along the length of a metre ruler.
What controls all the activities of the cell?
The nucleus
The nucleus is surrounded by the nuclear membrane and contains genes on chromosomes.
What is the function of the cytoplasm?
It is a liquid gel where organelles are suspended and chemical reactions take place.
What does the cell membrane control?
The passage of substances into and out of the cell.
Where does aerobic respiration take place in a cell?
In the mitochondria.
What is the average size of mitochondria?
1-2 µm in length and 0.2-0.7 µm in diameter.
Where does protein synthesis occur?
In the ribosomes.
Fill in the blank: Plant cells have all the features of a typical animal cell, but they also have _______ needed for different functions.
additional features.
What are chloroplasts responsible for?
Photosynthesis.
What is the primary component of the plant cell wall?
Cellulose.
What is the average length range of plant cells?
10-100 µm.
True or False: Algae are classified as plants.
False
Algae are classified as part of the kingdom - the protista.
What is one key difference between plant and animal cells?
Plant cells make their own food through photosynthesis.
What is the function of the vacuole in plant cells?
Storage and maintaining turgor pressure.
What structure in animal cells is responsible for controlling the movement of substances?
The cell membrane.
What does the nucleus do?
Controls all the activities of the cell and is surrounded by the nuclear membrane that contained genes in chromosomes.
What is the role of the cytoplasm?
A liquid gel in which organelles are suspended and where most of the chemical reactions take place.
What is the role of the cell membrane?
Controls the passage of substances such as glucose and mineral Jon’s into the cells and urea or hormones out of the cell.
What is the mitochondria?
Aerobic respiration occurs
What are ribosomes?
Protein synthesis occurs
What do plant cells have that typical animal cells do not?
Features needed for their very different functions
Plant cells contain structures like chloroplasts and a cell wall.
How are algae classified in modern taxonomy?
Part of the kingdom protista
Algae were historically classified as plants.
What is the composition of the cell wall in plant and algal cells?
Cellulose
The cell wall strengthens the cell and provides support.
What is the function of chloroplasts in plant cells?
Photosynthesis
Chloroplasts contain chlorophyll, which absorbs light for food production.
Where are chloroplasts found in a plant?
In all the green parts of the plant
Root cells do not have chloroplasts as they do not photosynthesize.
What is the size range of a chloroplast?
3-5 micrometers long
Chloroplasts are relatively small organelles.
What is a permanent vacuole, and why is it important?
A space in the cytoplasm filled with cell sap that keeps cells rigid
This rigidity supports the plant structure.
What is the role of chlorophyll in plants?
To absorb light for photosynthesis
Chlorophyll is the green pigment found in chloroplasts.
Which type of microscope is used to examine plant cells?
Light microscope
A light microscope allows for the visualization of cell structures.
What structures should you see when examining a plant cell under a microscope?
Cytoplasm, nucleus, chloroplasts, permanent vacuole
Structures may vary between different types of plant cells.
True or False: All plant cells contain chloroplasts.
False
Root cells do not contain chloroplasts.
Fill in the blank: Algal cells perform photosynthesis and have features similar to _______.
Plant cells
Algae were historically classified alongside plants.
What is the primary function of the cell wall in plant cells?
To provide strength and support
The cell wall is made of cellulose.
Name two features unique to plant cells.
Chloroplasts and permanent vacuoles
These features are not found in animal cells.
What are eukaryotic cells
They all have a cell membrane, cytoplasm and genetic material enclosed in a nucleus.
What are bacteria?
Single cells living organisms and prokaryotes.
What do bacteria have?
Cytoplasm and cell membrane surrounded by cell wall but no cellulose
What are prokaryotic cells?
Genetic material is not enclosed in a nucleus and the bacterial chromosome is a single DNA loop found free in cytoplasm.
What can prokaryotic sometimes contain?
Plasmids - extra ring of DNA
Slime capsule
Flagella
What does a dime capsule do?
Protect the cell
What do flagellum do?
A long protein strand that helps them move.
What is a specialized cell?
A cell that becomes specialized to carry out particular jobs.
What are nerve cells like?
Carry electrical impulses around the body and provide a rapid communication system. They have lots of drendrites to connect to other nerves. An axon that carries the impulse. Never endings and synapses adapted to pass impulses between cells using transmitter chemicals. Lots of mitochondria to provide energy needed for transmitters. Myelin sheath for insulation.
What are muscle cells like?
They contract and relax and work together in muscles. They contract and relax in pairs to move the bones if a skeleton and contract the food through your gut. They contain special proteins that slide over each other making the fibers contract. They contain many mitochondria to transfer energy needed for chemical reaction. They store glycogen to be broken down and used in cellular respiration.
What are sperm cells like?
Usually released a long way from the egg they will fertilize and contain genetic information from male parent. They have a king tail to help them move through water or the reproductive system. The middle section is full of mitochondria to transfer energy needed in tail. Gagne acrosome stores digestive enzymes to break down outer layers of egg. Large nucleus containing genetic information.
Root hair cells
Found close to tops of growing roots. Need to take in lots of water and ions. Close to xylem. They greatly increase surface area available for water to move into cell. Have a large permanent vacuole to speed up movement of water in osmosis from soil to cell. Have many mitochondria that transfers energy needed for active transport of mineral ions.
Photosynthetic cells
Help plants make their own food by photosynthesis. Contain specialized chloroplasts containing chlorophyll that trap light needed. Usually positioned in continuous layers in leaves and outer stem to absorb as much light as possible. Large permanent vacuole to help keep cell rigid due to osmosis.
Xylem
Transports water and mineral ions from roots to leaves and shoots. Supports the plant. Cells are alive when first formed but lignin builds up spiral in cell wall and cells die forming long hollow tubes. The spirals and rings of lignin make them very strong and help withstand pressure.
Phloem
Specialized transport tissue carried food made by photosynthesis. Phloem cells are alive. Cell walls break down between cells to form sieve plates proteins that allow water carrying dissolved food to move up and down tubes. Lose a lot of internal structure but are supported by companion cells and mitochondria in these transfer energy to move food up and down plant.
