Chapter 3 Flashcards
What is a plasma membrane?
~ “Skin” of cell
~ Protects and supports cell
~ Controls everything that enters and leaves the cell
Parts of a Cell
- Plasma membrane
- Cytoplasm
- Ribosomes
- DNA
What is cytoplasm?
Inside plasma membrane
Made up of cytosol
What are ribosomes?
Organelles that make proteins.
A structure In the cytoplasm.
What is DNA?
A nucleloid acid in cells that contain genetic information that cells need to make proteins
Selectively preamble
The ability to allow only certain molecules to pass I’m and out of a cell
Vacuoles
Organelles that store substances in cells.
Flagella/cilia
Extensions in the plasma membrane that help organisms movie.
Cytoskeleton
Cellular “skeleton” that helps cell maintain it shape and holds organelles within the cytoplasm.
Nucleus
Largest organelle
Cells control center
Controls which proteins to make
Mitochondria
Organelle that provides energy to the cell.
Cells “power house” or “power plant”
Contains its own DNA
ATP
Energy carrying molecule
ER
Organelle that helps make and transport proteins and lipids
Rough ER
Studded with ribosomes
Framework for ribosomes
Makes proteins
Smooth ER
No ribosomes
Makes lipids and stores other substances
Vesicles help carry proteins
Golgi apparatus
Large organelle that processes proteins and prepares them for use in/outside of the cell.
Vesicles/vacuoles
Sac-like organelles that store and transport materials in a cell.
Chloroplasts
Plastids that contain green pigment chlorophyll
Large Cell
Smaller SA-V ratio.
Not enough SA to get rid of wastes and take in necessary substances
Small cells
Perfect to pass substances Across surface
Larger SA-V ratio
Plant cell vs. Animal cell
Plants cells: Chloroplasts Only certain organelles Makes own food Cell wall
Animal cells: Multi-cellular organism Nucleus and membrane bound organelles No cell walls, cell membrane Cannot make own food
Prokaryotes vs. Eukaryotes
Prokaryotes:
- No nucleus
- single cells(live on own)
- ones strand of DNA
- cell walls
- no organelles
Eukaryotes:
- nucleus
- part of Multi-cellular organisms (not single)
- membrane bound organelles
Diffusion
Movement of substances across the membrane
Concentration
Number of particles of substances per unit of volume
What are two basic ways the substances can cross the cell membrane?
- Passive Transport
2. Active Transport
Passive transport
~ Does NOT require energy
~ HIGH —> LOW concentration
Three types:
- Simple diffusion
- Osmosis
- Facilitated diffusion
Simple diffusion
~ substances move from the side of High concentration to the side of low concentration.
~ small hydropholic molecules
Osmosis
The diffusion of water across the membrane.
~ high to low concentration
~ moves until the concentration is the same of both sides
Three types:
- Hypotonic
- Hypertonic
- Isotonic
Hypotonic
Less solute, more water
Hypertonic
Less water, lots of solute
Isotonic
Solute level is equal inside and outside of the cell
Facilitated diffusion
Needs help from transport proteins
Two types of transport proteins:
1. Channel proteins
2. Carrier proteins
Channel proteins
~ form tiny holes in membrane
~ allows small water molecules to pass through the membrane
~ ion channels
Carrier proteins
~ bind with specific molecules/ions
~ change shape
~ Carry ions/molecules across the membrane
Simple Diffusion vs. Facilitated Diffusion
Simple Diffusion:
Things just move right across the membrane; no help needed; no tunnel
Facilitated diffusion:
Needs help from carrier proteins
Protein may have to change shape
Active transport
~ NEEDS energy
~ moves from LOW to HIGH Concentration
~ gets help from transport proteins:
1. Sodium potassium pump
2. Vesicles transportSodium Potassium Pump
Sodium ions pumped OUT of cell, potassium ions pumped INto cell.
Vesicles Transport
Helps large molecule cross the plasma membrane.
Two types :
1. Endocytosis
2. Exocytosis
Endocytosis
Moves substances into cells
Exocytosis
Vesicles fuse with the membrane
Moves substances Out of cell.
