01 Organelles

Cytoplasm

Cytosol + Organelles

Ribosome -function

assembles proteins from amino acids.

Proteins produced on the ER ribosomes are destined either for:

(a) secretion from the cell, such as occurs with peptide hormones like insulin and glucagon (b) packaging into cytoplasmic organelles, such as lysosomes and peroxisomes (c) embedding in the plasma membrane or organelle membranes, for example channel proteins

Smooth endoplasmic reticulum -function

(a) the production of phospholipids for cell membranes (b) synthesis of steroid hormones

Secretory Vesicles

Cell secretions - e.g. hormones, neurotransmitters - are packaged in secretory vesicles at the Golgi apparatus. The secretory vesicles are then transported to the cell surface for release.

Cell Membrane -Structure

It is made from two layers of phospholipid molecules, called a phospholipid bilayer.

Lysosome

Lysosomes contain digestive enzymes. Breaks down foreign material.

Mitochondrion -structure

Mitochondria are membrane bound organelles with a smooth outer membrane and a convoluted inner membrane.

Cell Wall

Protective barrier that maintains the shape of the cell. In plants it is made of cellulose (a polysaccharide). In bacteria it is made of peptidoglycans, in fungi it is made of chitin.

Membrane Proteins

Proteins are embedded in the membrane; some only penetrate part of the way through the membrane. Some span the whole membrane. Some form pores or channels for other molecules to move across the membrane.

Peroxisome

Rids the body of toxic substances. Important in the liver and kidneys which are the main sites of detoxification.

Rough Endoplasmic Reticulum -structure

Rough endoplasmic reticulum (rough ER) is a network of folded membranes with attached ribosomes.

Chloroplast

Site of photosynthesis in plants, contain the chemical chlorophyll.

Rough Endoplasmic Reticulum -Function

Synthesis, folding, and modification of proteins. Transport of proteins through the cell. Membrane production.

Golgi Body -structure

The Golgi Apparatus, also called the Golgi Bodies or Golgi Complex, is a system of folded membranes and vesicles in eukaryotic cells.

Cytoskeleton -structure

The cytoskeleton is a network of protein fibres throughout cells. The cytoskeleton of eukaryotic cells includes microtubules, actin microfilaments and intermediate filaments.

Cytoskeleton -function

The cytoskeleton is like an inner scaffold providing structure for the cell. The microtubles and filaments also create tracks for organelles to travel around the cell. The protein fibres can slide over each other, allowing the whole cell to move.

Cell Membrane

The membrane defines the boundary of the cell and controls what enters and leaves the cell

Mitochondrion -function

The mitochondrion is an organelle for aerobic cellular respiration, generating ATP (chemical energy).

Nuclear Membrane

The nuclear membrane, or nuclear envelope, is a double lipid bilayer containing pores through which molecules can enter or exit the nucleus.

Nucleolus

The nucleolus is where ribosomes are built from RNA and proteins. Ribosomes are a structure that travel from the nucleus to the cytoplasm through the nuclear pores.

Nucleus

The nucleus of the cell carries the genetic material, the DNA. Responsible for regulating all the activities of the cell.

Smooth Endoplasmic Reticulum- Structure

The smooth endoplasmic reticulum (smooth ER) is a network of membranes in the cytoplasm resembling the rough ER but without ribosomes.

Golgi body -function

This is where proteins are sorted and packaged into vesicles for delivery to the plasma membrane for secretion (release from the cell) or to other locations within the cell, such as lysosomes and peroxisomes. Modification of proteins and lipids received from the ER. Sorting, packaging, and storage of proteins and lipids.

Vacuole

Vacuoles and vesicles are both membrane-bound sacs, but vacuoles are larger. Plant cells have a large vacuole that is involved in the storage of water and wastes.

Smooth endoplasmic reticulum is abundant in

cells that produce steroid hormones. For example cells in the ovaries making estrogen

Golgi apparatus is abundant in

cells that secrete proteins, such as endocrine glands. For example, cells in the pituitary gland produce peptide hormones like growth hormone which are released into the blood stream.

Cytosol

fluid contents of the cell

Ribosome -Structure

made of rRNA and protein. Not membrane bound. They are found 'free' in the cytoplasm or attached to endoplasmic reticulum membranes (rough endoplasmic reticulum).