CELLS

Question 1

What are the membrane and organelles of animal cells?

Answer 1

The nucleus, Endoplasmic reticulum, ribosomes, golgi apparatus, lysosomes, mitochondria, microtubules, spindle fibres, centrioles.

Question 2

Explain the nucleus?

Answer 2

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.

Question 3

Explan the endoplasmic reticulum? (smooth and rough)

Answer 3

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.

Question 4

Explain what ribosomes are?

Answer 4

tiny organelles found in the cyptoplasm, made of protein and rRNA, site of protein synthesis.

Question 5

Explain the what the golgi apparatus are?

Answer 5

series of curved flattened sacs (cisternae), modifies proteinsed adding carbs, lipids or cofctors.

Question 6

Expain waht lysosomes are?

Answer 6

Formed by the golgi apparatus and they contain hydrolytic enzymes, important role in phagocytes, thick membranes.

Question 7

Explain what the mitochindria is?

Answer 7

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.

Question 8

Explain what microtubules are?

Answer 8

Hollow cylinders from the protein tubulin, forming cytoskeletonkeeping organelles in place.

Question 9

Explain what spindle fibres are?

Answer 9

Important in the movement of chromosomes during mitosis and meiosis.

Question 10

Explain what centrioles are?

Answer 10

assembly of spindle fibres during cell division are formed of microtubules.

Question 11

What are the membrane systems and organelles of plant cells?

Answer 11

Plant cell wall, secondary cell wall, middle lamella, plasmodesmata, chloroplasts, large vacuole.

Question 12

Explain the plant cell wall? (primary)

Answer 12

main component - polysaccharide cellulose as microfibrils, made up of many.

Question 13

Explain the plant cell wall? (secondary)

Answer 13

layers f microfibrils are orientated iin different directions.

Question 14

Exploain the middle lamella?

Answer 14

Made of the polysacchride pectin, calcium pectae forms cement to hold cells together, provides support.

Question 15

Explain the plasmodesmata?

Answer 15

Strands of cyptoplasm, provide gaps in cell walls allowing molecuels to pass through.

Question 16

Explain chloroplasts?

Answer 16

Bounded by a double membrane or envelope elcosign the stroma, site of photosynthesis (palisade layer of cells).

Question 17

Explain the large vacuole?

Answer 17

important in the storage of ions and water, developmetn of turgor for support.

Question 18

What are the differences between prokaryotic and eukaryotic cells?

Answer 18

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).

Question 19

Explain the phospholipid bilayer?

Answer 19

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.

Question 20

Why is the structure of the cell membrane described s the fluid mosiac model?

Answer 20

The phospholipieds can flow sideways although always keeping the biler arrangement with the protein molecules floating between the phospholipid.

Question 21

Draw a diagram of the of the phospholipid bilye? (fluid mosiac model)

Answer 21

refer to pg 64 in the textbook.

Question 22

Explain what a bacteriophage is?

Answer 22

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.

Question 23

Explain waht HIV is?

Answer 23

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.

Question 24

What are the differences between a light microscope and an electron microscope?

Answer 24

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)

Question 25

Why is a vacuum nessesary when usiing an electron microscope?

Answer 25

Because air molecules would deflect the beam.

Question 26

What is the equasion for magnification?

Answer 26

image size
Actual size = ———————-
magnification