Chapter 3 Flashcards
Cell Theory
- The cell is the smallest unit having the properties of life
- Every organism is composed of one or more cells
- All cells come from pre-existing cells through cell division
- Cells contain hereditary material, passed to daughter cells during cell division.
- The metabolic processes associated with life occur within the cell
What are the Two types of cells?
Prokaryotic and Eukaryotic
Bacteria, DNA is not enclosed in a nucleus, few if no organelles
prokaryotic cell
protozoa, plants, animals; nucleus, organelles
eukaryotic cell
study of cells
cytology
What are the three ways all cells are alike?
Plasma membrane, DNA, Cytoplasm
Outer covering of all cells, composed of lipids and proteins, encloses cell, controls movement of substances in and out, selectively permeable
plasma membrane
Contains cell’s genetic instructions, nucleus (eukaryotes) nucleoid (prokaryotes)
DNA
region between the plasma membrane and the DNA, filled with organelles, contains cytosol
Cytoplasm
composed of two layers and interspersed with proteins, lipids, cholesterol, and sugars
phospholipids
polar, hydrophilic
phospholipid heads
non-polar, hydrophobic, sandwiched in the center of the bilayer
Phospholipid tails
dissolved molecule or ion moves down a concentration gradient
diffusion
does not require energy
passive transport
diffusion of water across a semipermeable membrane in response to solute concentration gradients
Osmosis
lower solute concentration outside cell than inside cell. Water moves into cell, swelling it and causing it to pop (lyse)
hypotonic solution
higher solute concentration outside cell than inside cell. Water moves out of cell causing it to shrink/shrivel
Hypertonic solution
same solute concentration inside and outside cell. Water movement in and out of cell is balance.
isotonic solution
help solutes cross membranes, specific to a solute, provide a channel
transporter proteins
also called facilitated diffusion
passive transport
cell uses energy to move solutes against concentration gradients
active transport
ribosomes and centrioles (have no membranes)
structures
signal travels far away from cell that made it
endocrine system
signal travels to nearby or cells next to it
Paracrine system
cell releases molecule that acts on cell that made it
Autocrine system
pore in the membrane which allows for a movement in a favorable direction
ion channel
small molecule that binds to outside and opens it up
Ligan-Gated Channel
sensitive to changes in the membrane (certain amount of pressure allows it to open up)
Mechanically-Gated Channel