cells Flashcards
(22 cards)
what are specialised cells?
cells designed to carry out a particular role in the body
examples of specialised cells in animals
nerve cells, blood cells, reproductive cells
examples of specialised cells in plants
root hair cells, palisade cells, xylem cells, phloem cells
what is differentiation?
the processes by which immature cells become mature cells with specific functions
what is magnification?
the increase of an object when it is viewed through a microscope or other optical device
what is resolution?
a measure of the microscope’s ability to distinguish between two points which are close together on an object
how do bacteria reproduce?
splitting into two equal halves by binary fission
what conditions do bacteria need to reproduce?
food, activity, time, temperature, oxygen, moisture
how to create uncontaminated culture?
using petri dishes and agar
how is genetic information stored in the nucleus of a cell?
the DNA molecule is packaged into thread like structures called chromosomes
what is mitosis?
a process of cell duplication, in which one cell divides into two genetically identical daughter cells
where does mitosis occur?
in somatic cells
what are stem cells?
cells with the potential to develop into many different types of cells in the body
what are the risks of using stem cells in medicine?
mutations have been observed in stem cells for a number of generations and some mutated stem cells have been observed to behave like cancer - the uncontrolled growth causes a tumour to form
what are the benefits of using stem cells in medicine?
they are used to regenerate and repair tissues that have been damaged of affected by disease
what is the process of diffusion?
the random movement of a substance form an area of high concentration to an area of low concentration
examples of diffusion
-perfume
-balloons
-breathing
how does temperature affect diffusion?
higher temperatures increases the energy and therefore the movement of the molecules increasing the rate of diffusion
how does surface area to volume ratio relate to single celled and multicellular organisms?
single celled organisms have a very large surface area to volume ratio, however large organisms have a greater volume with a smaller increase in surface area
what is osmosis?
a process by which the molecules of a solvent pass from a solution of high concentration to a solution of low concentration through a semi-permeable membrane
what is active transport?
the process of moving molecules across a cellular membrane through the use of cellular energy
what is the difference between osmosis, diffusion and active transport?
diffusion is the movement of particles fron a higher to lower concentration, osmosis the the diffusion of water across a membrane, active transport moves particles from low to higher concentration
