chapter 2 Flashcards
What was the first microscopic structure described from?
- plants because of their rigid cell wall
- they were easier to see in earlier microscopes
- arrangement and organization were easier to visualize
Cell theory
- 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
What is the significance of the cell theory to biology?
- biology is the study of life
- looking at how things affect cells (bacteria and viruses)
- looking at how things came about or evolved
Plant cell size
- most are small (100micrometers)
- some plant cells are unusually large
Plant cell wall
- 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
What is the most abundant organic compound on earth?
- cellulose
- 85-90% of earths biomass is plants & plants are made mostly of cellulose
What is the function of cell walls
- act as a support structure by containing water pressure
What is middle lamella?
- 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
Microfibrils and cellular shape
- 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
Protoplast
- organelles within the cell wall
- ex. plasma membrane, nucleus, organelles, cytosol
Plasma membrane of plants
- similar to animals but associated with different proteins
Plastids
- 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
What is the significance of amyloplast?
- most common leucoplast
- store starch
Mitochondria vs Chloroplast
Similarities:
- have energy production mechanisms (e transport, ion gradient, ATP synthase)
- double membraned
- originate from endosymbiotic relationships
Differences:
- chloroplast can photosynthesize
Central vacuole
- 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
ER
- protein synthesis
- RER has ribosomes for protein synthesis
Golgi
- protein transport
- in a developing plant cell, cell wall components are transported out of the cell via the golgi
plasmodesmata
- cytoplasmic bridges
- movement of materials between cells
nucleus
- control center of cell
- directs protein synthesis and cell reproduction
nuclear pores
- how RNA gets out of nucleus
nucleolus
- concentrated area of RNA and protein within the nucleus
- ribosomal assembly
TC: did researchers create life with bacterial chromosome insertion?
- 2010; artificial production of bacterial chromosome transplanted into another bacterial cell
- researchers did not create life because they did not create cells
- cells are the basic unit of life
Skim
- moving into and out of cells
- cell division
vinicristin drug
- vinicristin is an anticancer drug from the Madagascar periwinkle
- it disrupts microtubule formation
- effective chemotherapeutic agent because it stops cancer cells from dividing (chromosomes are not segregated correctly so cell cycle is stopped)