Cells and Membranes

cell theory

the idea that all living things are made of cells, cells are the basic unit of structure and function, and all cells come from pre-existing cells.

Robert Hooke

named “cells” after observing cork

Anton van Leeuwenhoek

first to observe living cells under a microscope

Matthias Schleiden

concluded all plants are made of cells

Theodor Schwann

concluded all animals are made of cells

Rudolf Virchow

stated cells from pre-existing cells

prokaryotes

cell lacking a nucleus and other membrane-bound organelles

eukaryotes

cell with a defined nucleus and other membrane-bound organelles

organelle

specialized cell structure with a specific function

plant cell characteristics

cell wall, chloroplasts, large vacuole, autotrophic

animal cell characteristics

no cell wall or chloroplast, many small vacuoles, heterotrophic

cytoskeleton

provides shape, helps movement, transports material

nucleus

control center, holds DNA

rough ER

transports proteins, has ribosomes, connected to nucleus

smooth ER

makes lipids, transports materials

ribosome

site of protein synthesis

golgi apparatus

modifies, packages, and ships proteins and lipids

mitochondria

powerhouse, makes ATP

vacuole

stores water, minerals, and other materials

lysosome

digests waste with enzymes

centriole

helps with cell division

cell wall

protects and supports the cell

cell membrane

controls what enters/exits the cell

chloroplast

site of photosynthesis, makes sugar

fluid mosaic model

membrane is flexible and made of many parts embedded in the bilayer

selectively/semipermeable

allows some materials to pass, blocks others

importance of semipermeability

helps maintain homeostasis

phospholipid head

polar and hydrophilic

phospholipid tails

non-polar and hydrophobic

why phospholipids form a bilayer

heads face water, tails hide inside away from water

membrane proteins function

transport, identity, communication

cholesterol in membrane

strengthens/stabilizes membrane

carbohydrates in membrane

identify the cell

integral proteins

go through entire membrane

peripheral proteins

sit on the membrane surface

passive transport

moves materials without using energy (high to low)

diffusion

movement from high to low concentration

concentration gradient

difference in concentration between two areas

dynamic equilibrium

no net movement, molecules still move

osmosis

diffusion of water molecules across a semipermeable membrane

isotonic solution effect on cell

cell stays the same size

hypertonic solution effect on cell

cell shrinks (water leaves)

hypotonic solution effect on cell

cell swells/bursts (water enters)

facilitated diffusion

diffusion through proteins, no energy used

channel proteins

form tunnels for molecules/ions

carrier proteins

change shape to move molecules

active transport

uses energy, moves materials from low to high concentration

proteins used in active transport

pumps that use ATP

uniport

moves one substance in one direction

symport

moves two substances in the same direction

antiport

moves two substances in opposite directions

proton pump

moves h+ ions from low to high concentration, active transport

sodium-potassium pump

moves sodium out and potassium in, active transport

endocytosis

cell takes in large materials using vesicles

phagocytosis

cell membrane engulfs solid molecules (cell eating)

pinocytosis

cell membrane takes in fluid (cell drinking)

phagocyte

white blood cells that engulf harmful particles

exocytosis

cell releases large materials using vesicles

transport for neurotransmitter release

active transport via exocytosis