Cell Unit Part II

This area focuses on terms and processes that occur within the cell Physiology: – cell anatomy and basic function Cell Division: – mitosis and meiosis Metabolism: – Photosynthesis and respiration at the cellular level.

Transport in and out of the cell Diffusion: – The flow of material from a region of high concentration to low by random motion. This occurs with most material between the cell and nuclear membranes.

Types of solutions Hypotonic: – the cell has a lower concentration than the outside. The material being considered would prefer to enter the cell by diffusion. Hypertonic: – the cell has a higher concentration than the outside. The material being considered would prefer to leave the cell by diffusion.

Isotonic: – The concentration of each material is equal on both sides. Even though the concentration is equal. Passage back and forth is occurring. We call this dynamic equilibrium or steady state.

Osmosis: – The transport of water by diffusion.

Which substance is hypotonic? Which substance is isotonic? Which substance is hypertonic?

Cyclosis: simple organisms seem to have the cytoplasm moving around within the membranes. The reason for this is unclear, but is a form of transport so that all part has all material available. This is also called Cytoplasmic streaming.

Active Transport Is required when the particles have to move against a concentration gradient from low to high. Another reason for active transport is if the material is too large to pass through a pore, even in one exists.

Across a concentration gradient Some materials pass from low concentration to high. This happens in cell and nuclear membranes and well as the mitochondria. Such substances are usually ions such as sodium, potassium and iodine. To carry these across the exact mechanism is not known but it is a shuttle service. The ion is picked up and carried across and deposited.

Large molecule transport into the cell. The passage of large molecules too big to fit through the holes is called ENDOCYTOSIS. Two processes are used. 1) The plasma membrane folds inwards and engulfs the large particle into a food vacuole. This is called PHAGOCYTOSIS. 2) If the large particle is in liquid form or has a liquid involved it is called PINOCYTOSIS.

Large particles leaving the cell The reverse process is called EXOCYTOSIS. The large molecules are usually wrapped by the Golgi Apparatus so not to be broken down. Often these large molecules are proteins, hormones, or metabolic wastes.

Quick checkup 1.This organelle is responsible for cell respiration 2.This organelle packages things to help export from the cell or prevent breakdown 3.This cell structure when filled with water gives plants support. 4.This organelle is inside the nucleus

Checkup continued 5.What is the role of the ribosome? 6.What is the role of the Endoplasmic Reticulum? 7.What is the role of the lysosome? 8.Name for the term of all matter inside the cell? 9.Name two things plant cells have that animal cells don’t.

Assignment Read pages of the text. Describe the diagram on pg 128 in your own words.

Cytokinesis

Whitefish

Assignment Using the microscope, find an example of: – Prophase – Metaphase – Anaphase – Teleophase Label the stage on the image and hand in. You may use the microscope with the camera or find on a slide and draw.