1.1 Cell Biology Flashcards
Convert 1mm into micrometers
1 mm = 1000 μm
Convert 1μm into nanometres
1μm = 1000 nm
What is the function of the nucleus?
- Controls the cell’s activities
- It contains chromosomes that are made up of genetic material that carry the instructions for making protein and cell growth
What is a Cytoplasm?
A jelly-like substance where most of the chemical reactions needed for life take place
What is the function of the Cell Membrane?
Partially permeable structure that controls what goes in and out of the cell
What happens inside the Mitochondria?
The mitochondria is where aerobic respiration takes place, to release energy for the cell
What is the function of Ribosomes?
Ribosomes are where proteins are synthesised
What are the sub-cellular structures inside a plant cell, but aren’t in a human cell?
- Vacuole
- Cell Wall
- Chloroplasts
What is the function of the Permanent Vacuole
The permanent vacuole is filled with cell sap that stores nutrients and supports the cell by keeping it rigid
What is the function of the Cell Wall?
What is it made of?
Made of cellulose, which strengthens the cell
What is the function of chloroplasts?
Chloroplasts contain chlorophyll that absorbs light energy to carry out photosynthesis
Where are eukaryotic cells found?
Eukaryotic cells are found in Animal, Plant and Fungal cells
Propeties of Eukaryotic Cells
Sub-Cellular structures, Size
- Have a cell membrane, cytoplasm and nucleus
- 5 - 100μm in size
Where are prokaryotic cells found?
& describe their size
- Found in Bacteria
- Much smaller than eukaryotic cells
- 0.2 - 2μm in size
What sub-cellular structures do eukaryotic& prokaryotic cells have in common?
- Cell membrane
- Cytoplasm
- Ribosomes
What feature is in a eukaryotic cell are not in prokaryotic cells?
Nucleus
Where is the genetic material in a prokaryotic cell found?
The genetic material is enclosed in a single DNA loop in the cytoplasm and plasmids
What are Plasmids?
Plasmids are extra small rings of DNA
What is the function of Plasmids?
Plasmids have genes that can replicate and move between cells so that genetic information can be shared
How did eukaryotic cells come into existence?
They evolved from prokaryotic cells.
What do specialised cells do?
They carry out a particular function
Examples of Specialised Cells
Animals:
- Sperm Cell
- Nerve Cell (Neurone)
- Muscle Cell
Plants:
- Root Hair Cell
- Xylem
- Phloem
Sperm Cell
Nerve Cell
- Axon is long to carry impulses across the body
- Dendrites make connections with other cells
Root Hair Cell
- Long thin projections increase the surface area for absorption
- Many mitochondria to provide energy for active transport
Xylem and Phloem
Phloem:
- Elongated cells to transport sugars over long distances
- Have many mitochondria for active transport
Xylem:
- Lignin in walls to provide strength and support
- Hollow tubes with no end walls to allow water and minerals to flow easily
When do most animal cells differentiate?
Most animal cells differentiate at an early stage
Why do animal cells differentiate?
& how?
Animal cells differentiate to form different types of specialised cells to carry out a certain functions, by developing different sub-cellular structures
How is cell division restricted in mature animals?
Cell divison is restricted to replacement and repair
When and how do plant cells differentiate?
Plant cells have the ability to differentiate throughout their lives through the meristems
Give an example of differentiation in animals
From an early embryo to a specialised cell
PRACTICAL
How do we prepare the slide before using the microscope?
Preparing the Slide
- Put a small drop of water on the slide
- Place a tissue sample on the slide
- Add a few drops of iodine solution the stain the cells
- Lower a coverslip onto the tissue using a mounted needle to prevent air bubbles
PRACTICAL
How do we use a Light Microscope
After preparing the slide
- Place the slide on the microscope stage
- Look through the eyepiece and use the lowest power objective lens to find the cells
- Use the coarse adjustment knob to focus on the cells
- Use the fine adjustment knob to focus more clearly
- Switch to a higher power lens and use only the fine adjustment knob to focus
What is Magnification?
Magnification is how many times larger an image is seen through a microscope compated to the actual object
Formula for Magnification
Magnification = size of image / size of real object
What is Resolution
The ability to see or distinguish two or more points as separate points
Differences between the electron microscope and light microscope
What are the benefits?
- The electron microscope has a higher magnification and resolving power than the light microscope
- This has allowed us to see sub-cellular structures in finer detail
Bacteria multiply through binary fission
What is binary fission?
Binary fission is when one bacterial cell divides into two
How often can bacteria multiple in the best conditions?
Once every 20 minutes
