B1.1-Cell structure Flashcards
What are three common features of plant and animal cells (eukaryotes)?
1) Cell membrane; 2) Cytoplasm; 3) Genetic material in a nucleus.
Which are bigger; bacterial cells (prokaryotes) or eukaryotes?
Eukaryotes.
True or false? “Prokaryotic cells have a cell wall.”
True.
True or false? “Prokaryotic cells have a nucleus.”
False.
In what form is the genetic material in a prokaryotic cell?
A single DNA loop.
Name five common parts of animal and plant cells.
Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
Name two further features of a plant cell.
Chloroplasts, permanent vacuole (filled with cell sap).
Describe the function of the nucleus.
Contains the genetic material of the cell.
Describe the function of the cytoplasm.
The location of cellular reactions.
Describe the function of the cell membrane.
To determine what is allowed into and out of the cell.
Describe the function of the mitochondria.
Where aerobic respiration occurs to release energy.
Describe the function of the ribosomes.
To bond amino acids together to form proteins (protein synthesis).
Describe the function of the chloroplasts.
The location of photosynthesis.
Describe the function of the permanent vacuole.
A storage area for ions and water, sometimes pigments.
Which strong material is the cell wall of plant and algal cells made from?
Cellulose.
What is the definition of a cell?
The individual unit of an organism.
What is the definition of a tissue?
Cells of the same type working together to perform a specific function.
What is the definition of an organ?
A structure made from multiple tissue types to perform a specific function.
What is the definition of an organ system?
Multiple organs working together to perform a specific function.
Describe a specialisation of a sperm cell.
Mobile due to flagellum; many mitochondria to allow high energy release for movement; streamlined head; digestive enzymes in head to break down egg membrane.
Describe a specialisation of a nerve cell.
Many mitochondria to provide lots of energy for active transport; many proteins embedded in cell membrane to allow ion movement.
Describe a specialisation of a muscle cell.
Many mitochondria to provide lots of energy for contraction; many ribosomes to synthesise proteins.
Describe a specialisation of a root hair cell.
Elongated shape to increase surface area for ion absorption; many mitochondria to provide lots of energy for active transport.
Describe a specialisation of a xylem cell.
Little cell contents to allow easy movement of water and ions through each cell.
Describe a specialisation of a phloem cell.
Needs a companion cell to work optimally.
What is “cell differentiation”?
The process of a stem cell dividing and becoming a specialised cell.
When do most animal cells differentiate?
At an early stage of development.
What is different about plant cells’ differentiation?
They retain the ability to differentiate throughout life (e.g. a stem developing roots when planted in soil)
In mature animals, what is cell differentiation used for?
Repair and replacement of old/damaged cells.
What are the two advantages of electron microscopes over light microscopes?
- Increased magnification, 2. Increased resolution.
What is the “resolution” or “resolving power” of a microscope?
The ability to determine two close objects as separate images.
What are the three forms of equation used to calculate magnification (M), the image size (I) or the actual size of an object (A)?
- A=I/M, 2. I=A x M, 3. M=I/A
What is 1340000 nm expressed in standard form?
1.34 x 10^6 nm
What is 0.0000001 µm expressed in standard form?
1 x 10-7 µm
What is the difference between mm, µm and nm?
A factor of 1000.
By what process do bacterial cells divide?
Binary fission.
If provided with enough nutrients and a suitable temperature, how often can bacterial cells divide?
Around every 20 minutes.
Describe the two ways bacteria can be grown in a laboratory.
- In a nutrient broth solution, 2. On an agar gel plate/petri dish.
What is a “contaminant”?
An unwanted species of microorganism growing in your culture.
What should you do with Petri dishes and culture media before use?
Sterilise it at high temperature to kill contaminants.
How do you sterilise inoculating loops?
Pass them through a Bunsen burner flame before use.
How should a Petri dish be stored in school?
Upside down, with tape securing the lid.
What is the maximum temperature cultures should be incubated at in schools or colleges?
25°C
Explain why the maximum incubation temperature for bacterial cultures in schools is 25⁰C.
To avoid growing potential pathogens.
If you were asked to calculate the cross-sectional area of a circular clear area around a disinfectant, what equation would you use?
Pi r^2
What is a chromosome?
A coiled thread-like structure of nucleic acids (DNA) and protein found in the nucleus of eukaryotic cells.
