OCR Biology Master Flashcards

Om Sri Sairam two features of a plant cell that are not features of animal cells

cell wall
chloroplasts

One structure present in animal cells that is not present in plants cells

centrioles

describe the role of cytoskeleton [3]

1) cell support (structural)

2) movement of cilia

3) exocytosis

how do organelles in pancreatic cells work together to produce and release protein molecules from cells [5]

1 transcription from nucleus

2 ribosomes on the RER do protein synthesis

3 vesicles for transport of proteins

4 golgi processes and remofies proetins

5 vesicles fuse with plasma membrane

mammalian chest model: why do balloons expand when rubber sheet is pulled?

1 volume inside jar increases

2 pressure inside jar decreases

3 to below pressure in atmosphere

4 so air moves into balloons through glass tube

define tidal volume

1 volume of air inhaled

2 in each breath

3 during steady / regular breathing

how can this be demonstrated with the balloon model

1 up and down movememnts of rubber sheet

2 small steady and regular

define vital capacity

1 maximum volume of air

2 inhaled and exhaled in 1 breath

how can this be demonstrated with the balloon model

pull down on rubber sheet as far as possible and pushed as far as possible

why does tissue fluid not contain erythrocytes

1 gaps between endothelium cells too smalll

2 erythrocytes too large

3 to pass between endothelial cells

describe the role of haemoglobin in transporting oxygen around the body

1 high affinity for o2

2 o2 binds to haemoglobin in lungs

3 oxyhaemoglobin is formed

4 oxygen released in tissues

describe how hydrogencarbonate ions are produced in erythrocytes

1 co2 enters into erythrocytes

2 co2 combines with water

3 carbonic anhydrase

4 forms carbonic acid

5 carbonic acid dissocites to form hydrogencarbonate ions and hydrogen ions

Explain Bohr shift

1 Bohr shift

2 reduces affinity of Hb for o2

formation of heamoglobinic acid

prevents fall in pH / buildup of H+ in cells

what can be seen that aids the function of companion cells, using a microscope

1 many mitochondria

2 plasmodesmata

3 many ribosomes

4 many proteins in the plasma membrane

at what stage of life does cell differentiation begin

in the grex?

correct term for communication between cells

cell signalling

define homologous chromosomes

A pair of chromosomes that contain genes for the same characteristics