AP Bio Unit 2

Cells

Basic units of life

Emergent Properties

The organelles alone can do nothing, but if all of them are put together inside a cell membrane, “life'“ can emerge

Cytology

The study of cells

Cytologist

A person who works with cells

Prokaryotic Cells

Eubacteria and Algae

Prokaryotic Cells

evolved before the evolution of the nuclear membrane and nucleus

Prokaryotic cells

lack membrane bound organelles

Prokaryotic Cells

which is smaller, prokaryotic cells or eukaryotic cells

3.5 billion

It is believed that the first prokaryotic cells came into existence about ___ _______ years ago

stromalites

bacterial mounds

Eukaryotic Cells

These cells evolved after the evolution of the nucleus

Eukaryotic cells

all organisms on earth, other than eubacteria and archae are composed of these cells

Eukaryotic cells

these cells have a membrane bound nucleus and membrane bound organelles

Endosymbiotic Hypothesis

some prokaryotes begin to live together in symbiotic relationships with the smaller prokaryotes living inside larger ones. This gave the symbionts a survival advantage over other prokaryotes and eventually they evolved into Eukaryotic cells.

Lynn Margulis

who proposed endosymbiotic Hypothesis

1960s

when was the endosymbiotic hypothesis proposed

genetic annealing

DNA segments swapped to create a more permanent existence

Mitochondria and Chloroplasts

evidence for endosymbiotic hypothesis is found in these two things

unicellular

prokaryotes are ___________

protein and peptidoglycan

two main things that compose a cell wall in eubacteria

gram positive bacteria

stains blue, bacteria posses a THICK peptidoglycan layer

gram negative bacteria

stains red, this bacteria possesses a THIN peptidoglycan layer BETWEEN phospholipid layers

capsule

sticky substance that helps bacteria adhere to surfaces

Plasma “cell” membrane

this holds the cell together. Important for transporting substances into and out of the cell

Nucleus

this structure controls the activities of a cell by holding the DNA. The DNA serves as the instructions for building proteins.

Cytoplasm/Cytosol

This fluid filled space contains the nucleus and the other organelles. This area makes up most of the volume of the cell

Membrane-Bound Organelles

These enclosed structures specialize to carry out specific jobs within the cell

Phospholipid bilayer

makes up the majority of the cell membrane and also the organelle membranes

integral proteins

run completely through the bi-layer from the outside to the inside and function in the transport of molecules across the membrane. They also help to maintain the integrity of the membrane

peripheral proteins

located on one side of the membrane. They do not extend through the bi-layer. Can act as receptors for cell signals, as catalysts/enzymes, and as structural components of the cytoskeleton

molecule transport

each transport protein aids the transport of a specific molecule, ion, etc…

enzyme

the proteins of the cell membrane can act as an ______ to catalyze specific reactions

cell to cell communication and recognition

these proteins can help cells attach to each other and work together and/or communicate with each other

signal receptors

act to receive hormones or other signaling molecules which circulate in the blood or interstitial fluids

attachment points

some proteins act as attachment points for the cytoskeleton

cholesterol

this lipid molecule functions to keep the membrane from being too fluid, and too permeable to some small molecules.

Cholesterol

helps to keep the cell membranes of plant cells from freezing solid in very cold temperatures

Cholesterol

this lipid molecule helps to secure the proteins that are embedded in the membrane

Eukaryotic Cell

Plasma “cell” membrane, Nucleus, Cytoplasm or cytosol, Organelles

Plasma “cell” membrane

this structure holds the cell together and helps to regulate which substances can enter/exit the cell

nucleus

this controls the activities of a cell because it contains the DNA which acts as the instruction for building the cell’s proteins and determining its traits

cytoplasm or cytosol

this fluid-filled space contains the Organelles and makes up most of the volume of cells

Organelles

these structures specialize to carry specific functions within the cell. They divide up the labor and make the cell more efficient.

Nuclear Envelope

it is composed mainly of a double phospholipid bilayer and encloses the DNA

Nuclear Envelope

Contains pores (tunnels) composed from proteins which allow certain specific materials to enter/exit the nucleus. The messenger RNA must edit the nucleus and go to the ribosomes where it acts as the directions for making proteins

Chromatin phase

During most of the cell’s life cycle, the DNA is loose and spread-out throughout the nucleus. During this phase, the DNA looks like a bowl of plain spaghetti noodles.

Chromosome Phase

during this phase, the DNA coils around proteins called histones (in eukaryotes and archae). The coiling helps to organize the DNA so that it can be correctly distributed during the processes of nuclear and cell division

Nucleolus

this structure appears as a dark spot within the nucleus. It functions to make the ribosomal RNA (rRNA) and proteins which make up the cell’s ribosomes

Ribosomes

these are cell particles made up of rRNA and proteins. They are not usually considered to be organelles because they are not enclosed within a membrane. All cell types, both prokaryotic and eukaryotic have these. The presence of this in all cells reflects the common ancestry of all living things.

Ribosomes

the sites of protein synthesis

ribosomes

the cell’s normal proteins and enzymes are ALL made here

free ribosome

these float in the cytoplasm of a cell (Found in ALL types of cells) these ribosomes make proteins that will stay and function inside the cell that made them

bound ribosomes

These ribosomes are attached to the rough endoplasmic reticulum (These are ONLY found in Eukaryotes ONLY because only they have the RER) Bound ribosomes make proteins that will leave the cell to be used elsewhere. Many of these proteins acts as cellular communication signals or as antibodies to fight infections

Compartmentalization

Membranes and membrane-bound organelles in eukaryotic cells divide the cell into distinct locations where specific intracellular metabolic processes and enzymatic reactions can occur.

Endomembrane system

a group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins.

Endoplasmic Reticulum

composed of a network of small tubes called cisternae

Smooth Endoplasmic Reticulum

This structure helps with the synthesis of lipids, phospholipids, and steroids. It also helps with carbohydrate breakdown

Rough Endoplasmic Reticulum

This structure helps with protein synthesis, modification, and transport.

Golgi Apparatus

a membrane-bound structure which consists of a series of flattened membrane sacs, modifies proteins by attaching sugars to them.

Lysosomes

these membrane-enclosed organelles contain powerful hydrolytic enzymes and acids. Help to carry out the process of intracellular digestion. This process helps to breakdown materials within a cell.

Vacuoles and Vesicles

these membrane bound sac-like organelles act as phospholipid-based storage containers for the storage and release of macromolecules needed by the cell. Vacuoles can also serve to store wastes or toxins

Mitochondria

performs the process of aerobic cellular respiration. Creates ATP

Aerobic cellular respiration

Process in which the energy from food is transferred to the bonds of ADP and P to create ATP

Chloroplasts

The sites of photosynthesis in plants and algae

Chloroplasts

type of plastid or pigment container

Stroma

mostly watery space in between the thylakoids and outer membrane. Serves as the site of the Calvin Cycle

Calvin Cycle

metabolic pathway in which sugar is made

Endosymbiont Hypothesis

tries to scientifically explain the symbiotic relationships that led to the evolution of membrane-bound organelles and eukaryotic cells from once free-living prokaryotic cells

Lynn Margulis in the 1960s

who proposed endosymbiotic hypothesis

cytoskeleton

These structures help to support and protect the cell

cell wall of plant cells

composed primarily of the complex carbohydrate cellulose. It functions to provide support and protection to the plant. It may also protect the cells from bursting if they are exposed to hypotonic conditions

Cell walls of fungus

composed of the complex carbohydrate called Chitin. The functions of the fungal cell wall are similar to those of the plant cell wall

complex carbohydrates

Bacterial cell walls are mostly composed of