Cells and Microscopy Flashcards
What are the two types of cells?
Eukaryotic and prokaryotic.
What is the role of a nucleus in a eukaryotic cell?
It is the cell’s control centre and holds all the genetic material for that cell.
What is the role of the cytoplasm in cells?
It holds the internal components of the cell in place and protects them from damage.
What is the role of the cell membrane in a cell?
It is a barrier keeping the constituents of the cell in and unwanted substances out.
What is the role of mitochondria in a cell?
It generates energy for the cell to chemically function through respiration.
What is the role of ribosomes in a cell?
It is an enzyme catalysing chemical reactions and is the site of protein synthesis.
What is the function of the cell wall in a cell?
It provides structural strength and support, and also provide a semi-permeable surface for molecules to pass in and out of the cell.
What is the role of the vacuole in plant cells?
It helps to regulate and maintain water balance.
What is the role of chloroplasts in plant cells?
It performs photosynthesis during the day through the chlorophyll, which also contains a green pigment.
What is the role of pili in a prokaryotic cell?
It has a role in movement but is more often involved in adherence (sticking) to surfaces, which facilitates infection and is a key virulence characteristic (causing sickness).
What is the role of flagella in prokaryotic cells?
Assist cell movement through spinning.
What is the role of a plasmid in a prokaryotic cell?
They are non-essential, self-replicating DNA molecules, surrounded by a nuclear membrane. They consist of small, double-stranded DNA and have huge diversity in size.
What is the role of the nucleoid in prokaryotic cells?
It regulates growth, reproduction and function to the cell, containing all genetic material for that cell.
What is the role of the capsule in a prokaryotic cell?
It helps prokaryotes to stick to surfaces or other prokaryotes and prevent the cell from drying out.
What components do plant cells have that animal cells do not have?
A vacuole, chloroplasts and a cell wall.
How is a sperm cell specialised for its function?
It has a tail for swimming and mitochondria to release energy from the tail and an acrosome that releases enzymes, digesting egg membrane for fertilisation.
How is a nerve cell specialised for it’s function?
It is long to carry information and has many dendrites to connect to many other nerve cells.
What is meant by cell differentiation?
When a cell becomes specialised to carry out a particular function.
Why is an electron microscope better than a light microscope?
Electron microscopes have a higher magnification and resolution.
How has the development of microscopy improved over time?
Improvements in lens manufacture, using purer glass, helped to solve problems like colour distortion and poor image resolution. Mirrors were added to compound microscopes to add more light and improve the image.
What is the equation used to calculate magnification?
Magnification = Image size ÷ Actual size.
What does the prefix ‘centi’ mean?
A factor of one hundredth, 0.01 (cm)
What does the prefix ‘milli’ mean?
A factor of one thousandth, 0.001 (mm).
What does the prefix ‘micro’ mean?
A factor of one millionth, 0.000001 (µm).
What does the prefix ‘nano’ mean?
A factor of one billionth, 0.000000001 (nm).
What is the definition of a chromosome?
A structure made of DNA carrying a large number of genes.
How many chromosomes are in a human cell?
46 (23 pairs).
What is the process of mitosis?
Increase in number of mitochondria and ribosomes. Genetic material is copied, and chromosomes divide in half. Each set of chromosomes are pulled to opposing poles of the cell. Cytoplasm and cell membrane divide, forming two identical daughter cells.
What are the three stages in microbe investigation?
- Preparation (sterilising environment), preparing growth medium (food and nutrients for microbes).
- Inoculation (introducing microbes to environment).
- Incubation (using correct conditions for microbes to survive), using the growth curve (lag, exponential, stationary, and death phases), and observation of microbes reactions.
What is the definition of mitosis and where can it occur?
Mitosis is the process of cells dividing to form two identical daughter cells. This can occur in growth and repair.
What is the definition of a stem cell?
An undifferentiated cell that is capable of differentiating into other cell types.
Where are stem cells found?
In bone marrow, embryos and meristem tissue of plants.
What conditions may stem cells be able to treat?
Diabetes (transplanting lab-grown insulin producing cells for Type 1 diabetes) and paralysis (promoting formation of neurons).
What is one use of cloning in animals and plants?
Increasing the population of rare animal species. Producing large numbers of disease-resistant crops.
What is the process of using a light microscope? (RP)
- Place silde onto stage and use clips to hold slide in place.
- Select lowest power objective lens, position to almost touch slide by turning coarse focusing dial (risk of slide damage).
- Look through eyepiece, slowly turn coarse focusing dial, increasing distance between objective lens and slide until focused. Use fine focusing dial for more focus.
What magnification does an eyepiece have?
×10.
What is normally the lowest magnification of the objective lens?
×4.
Why do you use a stain in microscopy?
To make the cell components clearer.
Why are mitochondria and ribosomes not visible using light microscopy?
They are too small and they are not stained.
How can smaller components of cells be seen?
Using an electron microscope.
