Cell OrganellesCell Organelles

Cell OrganellesCell Organelles Organelle (“little

organ”) = a small structure in the cell that performs a specific function.

Membrane-bound organelles are found only in eukaryotic cells

CytoplasmCytoplasm Everything in a cell except

the nucleus is cytoplasm

Clear, gelatin-like, watery substance surrounding the organelles.

Maintains the shape and consistency of the cell.

Allows for chemical reactions necessary in metabolism

Cell MembraneCell Membrane Boundary of the cell

Made of a phospholipid bilayer, with protein molecules scattered all over

Regulates what comes in and out of the cell, provides for some protection of the cell and its organelles

NucleusNucleus Control center of the cell – has the

information needed to oversee the chemical reactions in cells (what is the counterpart in a factory?)

Contains DNA (either as chromosomes or chromatin), nucleolus and nuclear envelope

Surrounded by a double membrane called nuclear envelope

Usually the easiest structure to see under a microscope

Usually one per cell, but some cells have many nuclei

Nuclear EnvelopeNuclear Envelope Boundary of the nucleus

“Envelope” – because it a a double-membrane

Made of a phospholipid bilayer (like the cell membrane)

Regulates what comes in and out of the nucleus, has nuclear pores that allow a large molecule like RNA to move in and out of the nucleus.

Chromosome/Chromosome/ChromatinChromatin

Eukaryotic DNA has 2 forms: Chromatin- DNA that is loosely

coiled around a protein. When the cell in NOT dividing, DNA is in this form but cannot be seen in most light microscopes.

Chromosome- chromatin is condensed into chromosomes when the cell divides (mitosis/ meiosis). Humans have 23 pairs of chromosomes which contain all of your DNA. These are visible in a light microscope.

Has the genetic code that directs what proteins get made

NucleolusNucleolus A large, dense

area in the nucleus

Site of ribosome production

nucleolus

RibosomeRibosome

Site of protein synthesis (also known as translation)

Found attached to rough ER or floating free in cytoplasm

Not membrane-bound

Produced in a part of the nucleus called the nucleolus

Endoplasmic ReticulumEndoplasmic Reticulum A.k.a. “E.R.” (endo means

inside + cytoplasmic + reticulum means network = network of membranes inside the cytoplasm)

Connected to nuclear envelope

Rough ER: studded with ribosomes; it chemically modifies proteins

Smooth ER: no ribosomes; it makes lipids

Golgi ApparatusGolgi Apparatus

Looks like a stack of plates; membrane-bound

Stores, transports, and packages proteins

Molecules transported to and from the Golgi by means of vesicles

LysosomesLysosomes

Which organelles do lysosomes work with?

Garbage disposal of the cell

Membrane-bound

Contain digestive enzymes that break down big molecules and damaged organelles

VacuolesVacuoles Large central vacuole

usually in plant cells

Many smaller vacuoles in animal cells

Storage container for water, food, enzymes, wastes, pigments, etc.

Membrane-bound

What type of microscope may have been used to take this picture?

MitochondriaMitochondria “Powerhouse of the cell” –

found in BOTH plant and animal cells

Cellular respiration occurs here to release energy (ATP) for the cell to use

Has 2 membranes – outer and inner membranes (the latter is highly folded that increases surface area for cellular respiration

Has its own circular DNA and ribosomes (wonder why?)

ChloroplastChloroplast Found only in plant cells

and plant-like protists

Site of photosynthesis

Bounded by a double membrane – third membrane is “photosynthetic” - contains the green pigment chlorophyll

Contains its own DNA and ribosomes (why?)

CytoskeletonCytoskeleton

Acts as skeleton and muscle

Provides shape and structure

Helps move organelles around the cell, or move the cell itself

Made of three types of filaments

Only in eukaryotes

CentriolesCentrioles

During cell division – help assemble the spindle apparatus that moves chromosomes

Usually found only in animal cells

Made of microtubules arranged in a special way

Cilia and FlagellaCilia and Flagella Made of

microtubules arranged in a special way (similar to centrioles)

Extensions of (some) eukaryotic cells that have no cell wall

For movement

Cilia in throat cells Cilia in Paramecium Cilia in sperm cells

Cell WallCell Wall Found in plant,

fungus, and bacterial cells

Rigid, protective barrier

Located outside of the cell membrane

Made of cellulose (fiber) in plant cells

Quick ReviewQuick Review Which organelle is the control center of the cell?

Which organelle is responsible for converting food energy into usable energy and is present in ALL eukaryotic cells?

Which organelles are not found in animal cells?

Which organelle helps plant cells make food?

What does E.R. stand for?

Which organelles have something to do with making and packaging proteins?

Why are almost all organelles membrane-bound?

Identify the organellesIdentify the organelles