CELLS Flashcards
What are the membrane and organelles of animal cells?
The nucleus, Endoplasmic reticulum, ribosomes, golgi apparatus, lysosomes, mitochondria, microtubules, spindle fibres, centrioles.
Explain the nucleus?
contains DNA in chromosomes, 1 or more nucleoli which codes for ribosomal RNA, control centre of the cell, nuclear pores in the nuclear envelope in double membraned allowing the DNA code for protein synthesis to be taken to the cyptoplasm.
Explan the endoplasmic reticulum? (smooth and rough)
ROUGH - cosisits of flattened membrane bound sacs (cisternae), studded with ribosomes, transports proteins that were on attached .
SMOOTH - without ribosomes, lipid synthesis and detoxification of drugs.
Explain what ribosomes are?
tiny organelles found in the cyptoplasm, made of protein and rRNA, site of protein synthesis.
Explain the what the golgi apparatus are?
series of curved flattened sacs (cisternae), modifies proteinsed adding carbs, lipids or cofctors.
Expain waht lysosomes are?
Formed by the golgi apparatus and they contain hydrolytic enzymes, important role in phagocytes, thick membranes.
Explain what the mitochindria is?
enclosed with a double membrane, iner membrane is folded forming cristae, extending into the matrix of the mitochondrion, powerhouse of the cell, site of ATP synthesis during aerobic respiration. Diagram pg 58 textbook.
Explain what microtubules are?
Hollow cylinders from the protein tubulin, forming cytoskeletonkeeping organelles in place.
Explain what spindle fibres are?
Important in the movement of chromosomes during mitosis and meiosis.
Explain what centrioles are?
assembly of spindle fibres during cell division are formed of microtubules.
What are the membrane systems and organelles of plant cells?
Plant cell wall, secondary cell wall, middle lamella, plasmodesmata, chloroplasts, large vacuole.
Explain the plant cell wall? (primary)
main component - polysaccharide cellulose as microfibrils, made up of many.
Explain the plant cell wall? (secondary)
layers f microfibrils are orientated iin different directions.
Exploain the middle lamella?
Made of the polysacchride pectin, calcium pectae forms cement to hold cells together, provides support.
Explain the plasmodesmata?
Strands of cyptoplasm, provide gaps in cell walls allowing molecuels to pass through.
Explain chloroplasts?
Bounded by a double membrane or envelope elcosign the stroma, site of photosynthesis (palisade layer of cells).
Explain the large vacuole?
important in the storage of ions and water, developmetn of turgor for support.
What are the differences between prokaryotic and eukaryotic cells?
Size - eukaryotic bigger
Site of DNA - (P free incyptoplasm) (E membrane bound nucleus)
DNA organisation - (P circular without protein) (E chomosomes helically arranged DNA)
Ribosomes - (P small) (E large)
Internal structure - (P no complex organelles) (E membrane bound complex organelles).
Explain the phospholipid bilayer?
The hydrophillic heads are pointed out of the phospholipid bilayer into the whater and the hydrophobic tails are pointed inward to prevent breing near the water.
Why is the structure of the cell membrane described s the fluid mosiac model?
The phospholipieds can flow sideways although always keeping the biler arrangement with the protein molecules floating between the phospholipid.
Draw a diagram of the of the phospholipid bilye? (fluid mosiac model)
refer to pg 64 in the textbook.
Explain what a bacteriophage is?
DNA core, they inject the bacterial cell with new viruses and eventually the bacterial cell will erupt and new viuses are released to continue the cycle.
Explain waht HIV is?
Have and RNA core, they have a lipid bilayer containing glycoprotein, deliver RNA and enzyme reverse transcriptase which catalyses synthesis of DNA from RNA then DNA makes new viruses by synthesising new protein coats.
What are the differences between a light microscope and an electron microscope?
Refracted by - (L glass lenses) (E electromagnetic lenes)
Resolution - (L low) (E high)
Magnification - (L low) (E high)
Image formed on - (L retina of the eye) (E flourescent screen)
Detail - (L limited cellular detail) (E limited by dead specimens)
Advantage - (L veiw of living specimens, coloured) (E high resolution images)
Why is a vacuum nessesary when usiing an electron microscope?
Because air molecules would deflect the beam.
What is the equasion for magnification?
image size
Actual size = ———————-
magnification
