chapter 2 Flashcards
1
Q
What was the first microscopic structure described from?
A
- plants because of their rigid cell wall
- they were easier to see in earlier microscopes
- arrangement and organization were easier to visualize
2
Q
Cell theory
A
- all cells come from pre-existing cells (have a common ancestor)
- cells are the basic unit of life
- all life is made of 1 or more cells
3
Q
What is the significance of the cell theory to biology?
A
- biology is the study of life
- looking at how things affect cells (bacteria and viruses)
- looking at how things came about or evolved
4
Q
Plant cell size
A
- most are small (100micrometers)
- some plant cells are unusually large
5
Q
Plant cell wall
A
- primary cell wall is made up of cellulose and other polysaccharides
- secondary cell wall is made up of lignin
- all plants have a primary cell wall
- only certain plants have secondary cell walls
- secondary cell walls are normally involved in transport of water and minerals up woody stems
6
Q
What is the most abundant organic compound on earth?
A
- cellulose
- 85-90% of earths biomass is plants & plants are made mostly of cellulose
7
Q
What is the function of cell walls
A
- act as a support structure by containing water pressure
8
Q
What is middle lamella?
A
- holds cell walls together to form tissues
- is made of pectin
- pectin is in fruits and when boiled becomes sticky, thickening agent in jam/jelly
9
Q
Microfibrils and cellular shape
A
- shape of microfibrils influences cell shape
- transverse microfibrils result in longitudinal expansion (allows stem to grow up and roots to grow down)
- longitudinal microfibrils results in transverse expansion
- random cellulose microfibrils results in equal expansion in all directions
10
Q
Protoplast
A
- organelles within the cell wall
- ex. plasma membrane, nucleus, organelles, cytosol
11
Q
Plasma membrane of plants
A
- similar to animals but associated with different proteins
12
Q
Plastids
A
- unique to plants
- chloroplast: photosynthesis
- chromoplast: pigment but not photosynthetic pigment; store flavonoids and produce flower color
- leucoplast: white, non-pigmented and used for storage
- amyloplast: most common leucoplast, these are plastids that store starch
13
Q
What is the significance of amyloplast?
A
- most common leucoplast
- store starch
14
Q
Mitochondria vs Chloroplast
A
Similarities:
- have energy production mechanisms (e transport, ion gradient, ATP synthase)
- double membraned
- originate from endosymbiotic relationships
Differences:
- chloroplast can photosynthesize
15
Q
Central vacuole
A
- many plants have a central vacuole
- vacuole crystals form as a byproduct of metabolism
- crystals are needle like and are a defense against herbivores
- crystals are contained in the vacuole so they don’t harm the rest of the cell
