Five Types of Transport Across a Cell Membrane

Five Types of Transport Across a Cell Membrane

Transport is the cell’s way of achieving homeostasis - a stable condition.

Solutions:

Hypertonic: highly concentrated, lots of solute compared to another solution or area.

Hypotonic: dilute, little solute compared to a different solution or area.

Isotonic: equal concentrations of solute in two different solutions or areas.

1. Diffusion:

Moves: carbon dioxide, oxygen, small molecules

Direction: hypertonic to hypotonic

End result: isotonic

Energy: passive

1. Osmosis:

Moves: water

Direction: toward a high concentration of solute.

End result: isotonic

Energy: passive

1. Facilitated Diffusion:

Moves: large molecules move through carrier proteins

Direction: hypertonic to hypotonic

End result: isotonic

Energy: passive

1. Active Transport:

Moves: large molecules or charged particles through carrier proteins

Direction: hypotonic to hypertonic, low concentration to high concentration

End result: unequal concentrations

Energy: active

1. Endocytosis and Exocytosis:

Moves: large molecules that can’t move through the cell membrane

Direction: into a cell (endocytosis) or out of a cell (exocytosis)

End result: opening in cell membrane allows materials to move in or out.

Energy: active transport

Organelle / Function
Cell Wall / - gives support and shape to cells.
- made of cellulose.
Cell Membrane / - surrounds and protects the cell
- semi-permeable, it lets only certain things through.
Cytoplasm
(Cytosol + cell structures) / - jelly like fluid that is mostly water.
- it flows through the cell.
Cytoskeleton / - structure of microtubules and fibres that supports cell and allows movement.
Nucleus / - large, easily seen structure. It holds the DNA and controls the cell.
Nucleolus / - inside the nucleus, it is involved in protein synthesis.
Mitochondria / - the cell’s powerhouse, they break down large molecules releasing energy.
Rough Endoplasmic Reticulum / - a series of canals used to transport cellular materials.
- ribosomes make it look rough.
Smooth Endoplasmic Reticulum / - a series of canals without ribosomes.
Ribosomes / - located on rough ER and in the cytosol.
- location of protein synthesis.
Vacuole, Lysosomes, Secretory Vesicles / - a variety of “containers’ made of membranes.
- used for a variety of purposes.
Golgi / - stacks of vesicles.
Centrosome / - microtubule formation happens here.
Chloroplast / - changes light energy into chemical energy.

From Cells to Tissue to Organs to Organ Systems

There are many kinds of cells in the human body, such as muscle cells, bone cells, skin cells, blood cells, etc. Each kind of cell acts a little differently to suit its role in the body. For instance, muscles cells can stretch and snap back into shape (recoil) to suit the way a muscle needs function A nerve cell, on the other hand, doesn’t stretch or extend, but already has a very, very long tail (axon) down which a signal can be sent from one part of the body to another. The smallest units of the body – the cells – are individually too small to be seen by the naked eye. Yet when manylike cells are together, they form a tissue. Tissues are groups of cells with a common structure and function.

There are four main tissues in the body – epithelium, muscle, connective tissue and nervous tissue.

Epithelium (or epithelial tissue) is found all over the body with several functions. In the skin it protects us fromthe outside world, in the stomach and intenstines it absorbs. In the kidney it filters and in the glands it secretes.

Muscle tissue is responsible for body movement, moves blood, food, waste through body’s organs, and isresponsible for mechanical digestion.

Connective tissue wraps around, supports, cushions and protects organs. It stores nutrients and gives the skinstrength. As tendons and ligaments, it protects joints and attaches muscles to bone and each other. It includessome specialized tissues including cartilage, bone and blood.

Nervous tissue conducts impulses to and from body organs via neurons. It makes up the brain, spinal cord andnerves.

Two or more kinds of tissues together form each of our organs, like the heart or lungs. Many organs togetherform an organ system, like the digestive or respiratory system. All the organ systems together form anorganism, such as a person, dog or blue whale.

The body’s organization goes from cells to tissues to organs to organ systems to a whole working organism.

Organs

What is an Organ?
Definition: An organ is different types of tissue grouped together to perform a function.
Different kinds of Organs perform different functions.
Animal Organs
In the boxes below, describe the different tissues found in the organ and the organ’s jobs. / Plant Organs
In the boxes below, describe the different tissues found in the organ and the organ’s jobs.
Heart
What tissues are in this organ?
Blood, muscle, connective, epithelial and nervous tissues.
How does it work?
Nerves send messages from the brain to the heart: contract, relax. Blood is pumped into blood vessels which are made of connective and epithelial tissues. / Leaves
What tissues are in this organ? What do the tissues do?
1. Tissues that _make food______.
2. Tissues that ____give shape____.
3. Tissues that __form waxy material that protects leaves from drying out_.
Lungs
What tissues are in this organ?
Blood, muscle, connective, epithelial and nervous tissues.
How does it work?
Nerves relay messages from the brain telling the diaphragm to contract (breathe in) and relax (breathe out). The lungs take in O2, send it to blood vessels and expel CO2. / Stems
What tissues are in this organ? What do the tissues do?
1. Tissues that are firm and hold the leaves towards the sun.
2. Tissues that move water and other materials.
3. Tissues that move food from the leaves to other parts of the plant.
Stomach
What tissues are in this organ?
Blood, muscle, connective, epithelial and nervous tissues.
How does it work?
Muscles contract and relax to mix food. Tissues in the lining of the stomach produce chemicals that break down food. Water and food particles travel through connective tissue to blood vessels. / Roots
What tissues are in this organ? What do the tissues do?
1. Tissues that take in water and other materials from the soil.
2. Tissues that hold the plant in the soil.
3. Tissues that store extra food for the plant.