B1 biology Flashcards
what is a eukaryotic cell?
a cell which has a nucleus
what happens in the cytoplasm?
where the main chemical reactions of the cell take place
what is the cell wall made from?
cellulose
what is a specialized cell?
a cell made to have a specific job or function
what specialized cells are found in the small intestine?
Vili -
absorb nutrients through the feed you eat and send it where it’s needed
explain why it is important for egg and sperm cells to have a haploid nucleus
it is important because both cells should contain 23 pairs of chromosomes in the haploid
how are cilia cells used in the body ?
cilia cells help sweep dust, mucus and bacteria to the back of the throat so it can be swallowed
what does cell surface membrane do?
controls what is allowed in and out of the cell, like, liquids and holds in the cytoplasm
starch test
uses Iodine solution
negative test - remains yellow
positive test - turns blue/black
reducing sugars
uses benedict solution
negative result - bright blue
positive result - green/yellow or orange / red
proteins
uses Biurets reagent
negative test - light blue
positive test - purple
fats
Emulsion test - add a few drops of ethanol and shake.
then add a few drops of water and then shake.
negative test - remains clear
positive test - cloudy
what is the diffrence between quantitive and Qualitative ?
Qualitative - shows if a substance is present or not
Quantitive - shows how much of that substance there is
why are Enzymes known as Catalysts ?
because they speed up the rate of reaction so that they have a more comfortable tempreture to live at (optimum)
what is the molecule acted on by the enzyme called
the ‘substrate’
what is the part of the enzyme called where it meets the substrate?
the active site
what happens at optimum tempreture ?
the rate of reaction is at it’s fastest because the most kinetic energy is created in the reaction
what happens when enzymes denature ?
they become no longer complementry to their active site
why does substrate concentration plateu in the rate of reaction at times?
sometimes when you have more substrates than active sights in reaction the substrate concentration will plateu
rate of reaction =
amount of substrate used or amount of product formed / time taken
what is cellulose?
Cellulose is the main substance found in plant cell walls and helps the plant to remain stiff and strong.
describe the process of diffusion
1) diffusion is when particles of liquids and gas are constantly moving.
2) this causes an overall movement of particles from an area of higher concentration to an area of lower concentration.
how does diffusion occur in plant cells?
diffusion is the process that allows oxegen and carbon dioxide into and out of the cells
describe the process of Osmosis
1) a partially permeable membrane allows molecules of a certain size to pass through it (like water and oxegen)
2) sugars and salts molecules are too big so they cannot pass through the membrane
calculating mass % loss die to osmosis
change in mass = final mass - initial mass / initial mass x100
