Biology stupied questions part 3 Flashcards
if a nucleus measures 100mm on a diagram with a magnification of x10 000 what is the actual size of the nucleus
0.01mm
Express the following measurements in micrometres
A) 5cm
B) 25mm
C) 100nm
A) 5,000,000 micrometres
B) 25,000 micrometres
C) 0.1 micrometres
Express the following measurements in nanometres
A) 0.5mm
B) 0.4 micrometres
C) 0.1cm
A) 500,000 nm
B) 400 nm
C) 100,000,000 nm
Describe how you would make the slide and how you would illuminate the specimen under the microscope
to make the slide you would put the eukaryotic cell onto a microscope slide make sure it is a very thin layer of material if there is more than one layer of cells it will be difficult to see as there will be other cells underneath
then place two drops of iodine/potassium iodine solution on the cell then cover with a coverslip
the solution shows up the cell and the component of the cell should appear in violet in colour
put under optical microscope and light with the light microscope
examine the slide under the microscope using lower power then high power
adjust the iris diaphragm to reduce the illumination of the specimen
measure the length and width of the cell
why is it hard to view at a high magnification
At a high magnification, the eukaryotic cell will float in and out of focus, especially if the layer of water between the cover glass and the slide is too thick.
Name one substance that passes out of pores in the nuclear envelope to the cytoplasm
mRNA
name one substance that passes into the nucleus via the pores in the nuclear envelope
steroid hormones
describe the role of the nucleolus
contains RNA
where ribosomes are made
state three functions of the nucleus
transmits genetic information
provides instructions for protein synthesis
control centre of the nucleus
Name one type of human cell that does not contain a nucleus
red blood cells
Suggest why hydrolytic enzymes within cells need to be inside a vesicle
hydrolytic enzymes are what catalyse the digestion of proteins and break down unwanted organelles, if they were not in the lysosomes then they would possible catalyse the digestion and break down components that make up the cell therefore they need to be separate from the rest of the cell
if you carried out a physical training programme, how and why would you expect the number of mitochondria in your muscle cells to change
The mitochondria to increase in number as mitochondria are the site of ATP production during aerobic respiration when carrying out a physical training programme you are increasing the energy you are using therefore as mitochondria are self-replicating they can make more when energy needs to increase
Describe how the functions of ribosomes that are free in the cytoplasm that differ from the functions of ribosomes that are attached in the RER
ribosomes that are bound to exterior of RER are mainly synthesising proteins that are exported outside the cell
ribosomes that are free in the cytoplasm either singly or in clusters are the site of assembly of proteins which will be used inside the cell
Name the monomeric units of microtubules that occur in the cytoskeleton
tubulin
Describe the function of the cellulose cell wall found in plant cells
provide strength and support
maintains cells shape
contribute to the strength and support of the whole plant
permeable and allow solutions soluble and solvent to pass through
