Topic 1 - Cell Biology Flashcards
How are sperm cells specialised?
A tail to swim, half a set of DNA, lots of mitochondria for energy, the acrosome in the head contains enzymes so that it can pierce the egg
How are nerve cells specialised?
Insulated myelin sheath to send messages faster, dendrites to connect to other nerve cells
How are root hair cells specialised?
Large surface area, lots of Mitochondria for Active Transport
When do animal cells differentiate?
At an early stage
When can plant cells differentiate?
Many plant cells can differentiate throughout their life
Where are plant stem cells (meristem) located?
At the tips and the roots
How many pairs of chromosomes are in a typical body cell?
23 pairs (46 chromosomes)
What cells does mitosis make?
Normal body cells for growth and repair
Are the products of mitosis identical?
Yes
What is a stem cell?
An undifferentiated cell
List the stages of the cell cycle
Rest phase, DNA replicates, chromosomes arrange themselves along the centre of the nucleus, half of each chromosome moves to one side of the nucleus, nucleus divides, cell divides, back to rest phase…
What are the two types of animal stem cells?
Embryonic and adult stem cells
What can stem cells help with?
Diabetes and paralysis
List the stages of therapeutic cloning
Problem identified
Skin cell removed from patient
Nucleus of skin cell is inserted into empty egg cell
Egg is given electric shock
Mitosis starts
Embryo grows
Stem cells are removed from the embryo
Stem cells are forced to specialise
New cells used for treatment
What is an advantage of therapeutic cloning?
Stem cells are not rejected
Why can embryonic stem cells be a disadvantage?
Ethical reasons
Rapid division more likely to result in cancerous cells
Why is meristem useful?
Rare species can be cloned
Crops can be bred to be disease resistant
Definition of diffusion
The net movement of particles from an area of high concentration to an area of low concentration until equilibrium is reached
Factors which affect diffusion
Concentration gradient, temperature, surface area
Osmosis definition
The movement of water particles from an area of high concentration to an area of low concentration across a partially permeable membrane
Active Transport definition
The net movement of particles from an area of low concentration to an area of high concentration against the concentration gradient, across a partially permeable membrane (requires energy)
Are Bacteria Cells eukaryotic or prokaryotic?
Prokaryotic
How is the xylem specialised?
There are no top and bottom walls between xylem vessels, so there is a column of
water running through them. Their walls
become thickened and woody. They therefore support the plant.
Give examples of substances which have an increased surface area
Villi, alveoli, gills, roots
