Chapter 4: Cells Flashcards
1
Q
Cell Theory
A
- All organisms are composed of one of more cells
- Cells are the smallest living things
- Cells arise only by division of previously existing cells
2
Q
Why are cells small?
A
- Diffusion is only effective over small distances
- High demand on DNA, the larger the cell
3
Q
Cellular structure
A
- PLASMA MEMBRANE forms boundary of cell
- CYTOPLASM fills interior of cell
4
Q
Fluid Mosaic Model for plasma membrane
A
- made up of the phospholipid bilayer
- polar glycerol heads
- nonpolar fatty acid tails
5
Q
Interior of lipid bilayer
A
- nonpolar, no water-soluble molecules can cross
- Contains CHOLESTEROL, to prevent cell membrane from sticking to itself
- contains MEMBRANE PROTEINS, tunnels to allow certain substances through membrane
6
Q
Prokaryotes
A
- old
- single-cellled
- no nucleus or membrane-bound organelles
- genetic material in single, circular molecule
- small, 1-2 micrometers
- Kingdoms: eubacteria and archaebacteria
7
Q
Eukaryotes
A
- new
- single or many cells
- have a “true” nucleus and membrane-bound organelles
- genetic material organized and in nucleus
- larger, 2-1000 micrometers
- Kingdoms: protista, fungi, plantae, animalia
8
Q
Cell wall
A
- exists in plants, fungi and many protists beyond plasma membrane
- provides protection, maintains cell shape, prevents excessive water loss/uptake
9
Q
Chloroplasts
A
- exist in all plants and many protists
- site of photosynthesis
- energy-capturing center
- double membrane
10
Q
Central vacuole
A
- in plants, help with retaining structure
11
Q
Centrioles
A
- in animals and most protists, assist with mitosis (cell division) by assembling microtubules
12
Q
Chromosome
A
DNA of eukaryotes is packaged into segments and associated with protein, this complex is called a chromosome.
13
Q
Nucleus
A
- Site for subunits of ribosome to be synthesized
14
Q
Rough ER
A
- system of internal membranes
- covered in ribosomes
- dedicated to protein modification/synthesis
15
Q
Smooth ER
A
- adds carbs and fats to ER
16
Q
Golgi bodies/complex/apparatus
A
- flattened membranes scattered throughout the cell
- packages things from ER
17
Q
Lysosomes
A
- clean-up crew, contain digestive enzymes
18
Q
Peroxisomes
A
- isolate certain types of chemical reactions
19
Q
Mitochondrion
A
- cellular respiration, cellular powerhouse
- extracts energy from organic molecules through oxidative metabolism
- double membrane
20
Q
Cytoskeleton
A
- internal framework of protein fibers
- anchors organelles to fixed locations
- supports the shape of the cell
- helps organize ribosomes and enzymes needed for synthesis activities
21
Q
Diffusion & osmosis
A
- molecules diffuse down a concentration gradient from higher to lower concentration
- osmosis = diffusion of water
22
Q
Facilitated diffusion
A
- needs a transport protein/tunnel (still passive transport)
23
Q
Aquaporins
A
- selective channels that allow water to diffuse through plasma membrane
24
Q
Osometric concentration
A
- concentration of all molecules dissolved in a solution
25
Q
Hypertonic solution
A
- higher concentration of water on the inside of the cell
- the water moves out and the cell shrivels
26
Q
Hypotonic solution
A
- higher concentration of water on the outside of the cell
- water moves into the cell and the cell lyses
27
Q
Endocytosis
A
- brings substances inside the cell
- Phagocytosis: “cell eating,” solid matter
- Pinocytosis: “cell drinking,” liquid matter
28
Q
Exocytosis
A
- discharges substances out of the cell
29
Q
Active transport
A
- utilizes protein channels
- energy is used to pump substances against the concentration gradient
- allows cells to maintain specific concentration of certain molecules
30
Q
Sodium-potassium pump
A
- uses ATP to pump 3 Na+ out of the cell and 2 K+ into the cell
- generates a concentration gradient with more Na+ outside of the cell than inside
- purpose: for conduction of signals along nerve cells, and transportation of important molecules into the cell against their concentration gradient
