Organelles of Cells

*Ribosome Structure*

Two subunits made of ribosomal RNA (rRNA) and proteins; free or bound

Microfilaments

Support cell shape Change shape of cells (ex muscle contraction and cytokinesis) Made out of actin protein. located just around the cell membrane)

*Vesicles*

"Transportation Vehicles" specialize in moving products into, out of, and within a cell.

*Vesicle structure*

membrane bound sac

*Nucleus structure*

1) nuclear envelope 2) nuclear pores 3) chromosomes 4) nucleolus

*Smooth ER structure*

membranous tubules and flattened sacs with no attached ribosomes

What is mRNA?

messenger RNA; directs protein synthesis.

How many chromosomes does one cell have?

46 (23 pairs)

Flagellum

A long, hairlike structure that grows out of a cell and enables the cell to move. Propels the cell by an undulating whiplike motion.

endomembrane system

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

Centrosome

A structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division. A centrosome has two centrioles.

*Chromatin structure*

A substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones

Anchoring Junction

Acts like stables that tightly hold cells in place. (important in muscle cells, skin tissues)

Lysosomes

An organelle containing digestive enzymes to break polymers into monomers vesicles of digestive enzymes

*Chromatin*

Complex of proteins and DNA that appears as a diffused mass within the nucleus.

*Nucleus*

Contains and protects the cell's genetic material (DNA). Controls the cells activities by directing protein synthesis. "command center"

What is the function of the nuclear envelope?

Controls the flow of materials into and out of the nucleus through its protein-lined pores.

Golgi Apparatus

Finishes, sorts, tags, and ships products through vesticles Think of UPS! a stack of flattened membranes and associated vesicles close to the nucleus

Microtubles

Form the cell shape and support Tracks for motor proteins (vesicles, chromosomes during cell division) Forms Cilia/flagella Made out of protein subunits

Cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion Short, numerous appendages that propel paramecium

Extracellular Matrix

Helps hold cells together in tissues and protects and supports the plasma membrane. Main component: glycoproteins bonded with carbohydrates --> form strong fibers outside the cell.

Gap Junctions

Like tunnels So substances can move from cell to the other. Important for cell to cell communication. (Ex: Heart tissue)

What is an example of an area of the body that will be rich with the Smooth ER?

Ovaries and Testes; synthesizes *steroid* hormones. Liver; helps process *toxins* (drugs, alcohol, and other potentially harmful substances.) Muscle; calcium *ions* rush from the Smooth ER and into the cytosol and trigger contraction of the cell.

Mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production. From glucose to ATP Has an outer membrane and an inner one that is folded to form cristae. Inside the inner membrane is the matrix containing enzymes, a circular DNA molecule, and ribosomes.

*Rough Endoplasmic Reticulum*

Processes proteins for export out of the cell. (processed into vesicles) membrane connected to the nuclear envelope and extends throughout the cell. Ribosomes are attached

Intermediate Filaments

Reinforce cell shape Anchor organelles Fibrous proteins coiled together

Vacoules

Store water and nutrients in the cell. Temporary storage compartments in cells, sometimes used to store waste.

*Ribosome*

The enzyme that synthesizes proteins (takes amino acids and puts them together according to the DNA code provided the the mRNA) (Can be free or bound) "protein making machine"

Peroxisomes

metabolic compartments that do not originate from the endomembrane system. Some break down fatty acids and are used as cellular fuel. Some detoxify harmful compounds. Some convert toxic by-product to produce water.

Tight Junctions

To prevent fluid from moving across a layer of cells (digestive tract, skin, any linings)

What is the structure of the endoplasmic reticulum?

a network of flattend sacs and tubules around the nuclear envelope.

What assembles with rRNA to form ribosomes?

assembles with proteins brought in from the cytoplasm (makes ribosome subunits) The subunits then will exit to the cytoplasm where they will join with functional ribosomes.

Plasmodesmata

channels through cell walls that connect the cytoplasms of adjacent cells

What structure is DNA stored as within the nucleus?

chromosomes

*Nucleolus structure*

dense, nonmembranous body composed of protein and RNA molecules within the nucleus

What is the largest component of the endomembrane system?

endoplasmic reticulum (ER) "major manufacturing site"

*Smooth Endoplasmic Reticulum*

functions in metabolic processes. *Makes lipids and helps remove harmful substances* from the cell (breaks down toxins) as well as s*tores ions* (found in muscular areas of the body)

What is the double membrane enclosing the nucleus?

nuclear envelope

What organelles are included within the endomembrane system?

nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, various types of vesicles + vacuoles, and the plasma membrane.

What types of lipids does the Smooth ER make?

oils, phospholipids, and steriods.

Chloroplasts

organelles that capture the energy from sunlight and convert it into ATP & Carbohydrates has a double membrane, stroma (thick inner membrane), thylakoids (network of inner connect sacs), grana (each singular sack), granum (each stack of sacs)

What area in the body might contain a lot of ribosomes?

pancreas

*Nucleolus*

produces ribosomal RNA (rRNA) which is synthesized by the DNA. dense, nonmembranous body composed of protein and RNA molecules within the nucleus

What does the nucleus direct?

protein synthesis

Cell Wall

rigid extracellular structure that protects cells but also provides the skeletal support that keeps plants upright on land. Consists of fibers of cellulose embedded in the matrix of other polysaccharides and proteins.

What two locations are ribosomes found in the cell?

suspended in the cytosol (free), or attached to the endoplasmic reticulum (bound).

What is protein synthesis?

the process of making proteins by using the information present in the DNA

What happens to chromatin just prior to cell division?

the thin chromatin fibers coil up into chromosomes.

What do the organelles within the endomembrane system specialize in?

they either interact in the synthesis, distribution, storage, and export of molecules.