AP Bio Unit 2: the Cell

Cell Theory

All living things are made of cells. They area a basic unit of life that come from cell division.

Magnification equation

Magnification = image size/actual size

Endosymbiotic Theory

Evidence that some organelles within cells were at one time free living cells themselves.

Prokaryotes

First cells—simple cells. No nucleus or membrane.

Eukaryotes

Complex cells—multicellular or unicellular. Has nucleus and membrane.

Founders of the Cell Theory

Matthias Schleiden (plants) & Theodore Schwann (animals)

Rudolph Virchow studying human diseases

All cells come from pre-existing cells.

Diffusion

Net movement of molecules from regions of high concentration to low concentration in random motion. The thing that determines cell size.

Organelles

Perform various functions for a cell (found in the cytoplasm).

Nucleus

The control organelle. It contains the DNA in chromosomes and is bounded by a nuclear envelope (membrane). BIGGEST ORGANELLE

Chromatin

DNA spread out

Chromosomes

DNA condensed

Nuclear Envelope

Double membrane surrounding nucleus (nuclear membrane).

Nucleolus

Makes ribosomes that make proteins, max of 3 in one nucleus

Plasma Membrane

Surrounds outside of ALL cells. Double layer of phospholipids and proteins.

Phospholipids

Heads have glycerol and are hydrophilic, tails have fat and are hydrophobic.

Cell Membrane in Plants

Lies immediately against the cell wall in plant cells

Cell Wall

A rigid layer that lies outside of the cell membrane. Non-living with pores to let things in/out

Cytoplasm

Jelly-like substance enclosed by cell membrane. Provides a place for chemical reactions and gives cells their shapes.

Cytoskeleton

Helps cells maintain cell shape. Made of proteins which help move organelles around.

Microfilaments

Thread like and made of actin

Microtubules

Tubelike and made of tubulin

Centrioles

Help to pull chromosome pairs apart to opposite ends of the cell. ONLY IN ANIMAL CELLS

Mitochondria

The powerhouse of the cell. Generates cellular energy and is the site of cellular respiration.

Cristae

Inner membrane of mitochondria

Matrix

Outer membrane of mitochondria

Endoplasmic Reticulum (ER)

Network of hollow membrane tubules that connect to the nuclear envelope and cell membrane.

Rough Endoplasmic Reticulum (Rough ER)

Makes products for use outside of the cell, ribosomes are made and threaded into interior

Smooth Endoplasmic Reticulum (Smooth ER)

Makes products for use inside the cell, makes membrane, regulates calcium, destroys toxic substances.

Ribosomes

Protein factories for the cell that join amino acids to make proteins. Can be attached to Rough ER or free in cytoplasm

Golgi Bodies/Apparatus/Complex

Transport vesicles that have a shipping face and a receiving face

Golgi Bodies

Modify, sort, and package molecules from ER for storage or transport out of the cell.

Lysosomes

Breaks down food, bacteria, and worn out cell parts for new cells. Release enzymes to break down and recycle cell parts.

Phagocytosis

How cells take in food

Autolysis

Program for cell death

Cilla

Function in moving cells, fluids, or small particles. A bunch of short and numerous tails

Flagella

Function in moving cells, fluids, or small particles. Long tails, normally just 1-3.

Vacuoles

Fluid filled sacks for storage. Stores sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes. None in bacteria.

Contractile Vacuoles

Regulate water intake by pumping excess (homeostasis). Found in unicellular protists like paramecle.

Chloroplasts

Use energy from sunlight to make food. Have a double membrane. Only in producers.

Thylakoids

Modified membrane sacks, when stacked called Grana. Stroma is a gel material that surrounds them.

Membranes are fluid mosaics

Must be fluid to work

Membrane (Fluid)

Phospholipid bilayer which is flexible allows for shape but aren’t bonded to each other. Dynamic ever-changing.

Integral Proteins

Span entire membrane and attached to it

Peripheral Proteins

Attached to one point

Cholesterol

A eukaryote which modulates the membrane’s fluidity so it doesn’t explode.

SO TINY

Smallest unit that can carry out all the processes of life

Diffusion

Passive; disperses randomly from high to low.

Osmosis

Passive; molecules move down the gradient. (high to low)

Membrane is semipermeable

water can move through membrane

Cell Membrane

Not active or passive; all about proteins moving around in it.

Facilitated Diffusion

Passive; special carrier molecules that form the protein channel bind to carrier molecules.

Endocytosis & Exocytosis

Active; transfers materials in/out of membrane.

Endocytosis

Part of the surface membrane forms a sack around a group of cells to transfer.

Exocytosis

Exocytosis

a cellular process where substances are expelled from a cell

Phagocytosis

takes in food or large molecules

Pinocytosis

takes in liquid molecules

Receptor-mediated endocytosis

takes in hormones, LDL, VIP molecules

Sodium/Potassium Pump

Active; a pump which transfers sodium and potassium between the membrane.

Hypotonic

more concentration in the cell then the water surrounding it

Hypertonic

more concentration in the water around the cell then in it

Isotonic

concentration is equal in the cell and water surrounding it