intro to the cell

Question 1

cell theory

Answer 1

1. all organisms consist of one or more cells
2. basic unit of life
3. all cells arise only from pre-existing cells

Question 2

limitations on cell size

Answer 2

• surface area/volume ratio
• diffusion rate of molecules
• need for adequate concentrations of reactants and catalysts: high cc increases freq of collisions
• diffusion takes seconds in a mammal cell: inefficient so small environments needed

Question 3

circumvent limitations in cell size

Answer 3

• microvilli: too small surface: increases surface area of membrane
  -shape: a small prismatic shape is not always suitable for exchanges
• increasing volume: small cells fuse together: muscle fibers: shortening and force generations

Question 4

variation in organism size

Answer 4

• accounted for by changes in cell number
• when ploidy is increased the cells tend to have a bigger size

Question 5

human cells

Answer 5

• most abundant types are RBC (84%), platelets, blood precursors
• 411 cell types (gastrulation, trans-differentiation…)
• vary in internal structure, morphology, life history
• still more alike than different
• cells deriving from same germ layers are in same cluster. same types are similar but are mutable biological units
• prominent features linked to specific function (differentiation)
• basic functions include survival, growth, reproduction

Question 6

human cell dimensions

Answer 6

• morphology linked to function (natsec)
• smallest is sperm
• largest is egg
• can recognise cell types from morphology
• distinctions require molecular markers wen differences are subtle

Question 7

prokaryote

Answer 7

• 1-5 microns
• unicellular
• capsule, cell wall, membrane, cytoplasm (single compartment), DNA as singular circular chromosome, pili, flagella, ribosomes

Question 8

intracellular compartments

Answer 8

• allows high cc of enzymes and reactants
• segregations allows different reactions at the same time and diff conditions (pH)
• organelles are specialised for functions

Question 9

EUK

Answer 9

• bigger
• organelles, nucleus
• multiple linear chromosomes
• 10-100 microns
• associated in tissues when multicellular

Question 10

cell cultures

Answer 10

• study cells outside tissues
• cultured in vitro
• cancer cells useful as immortal