CELL STRUCTURE AND FUNCTIONS

The Cell as Highly Organized Structure

THE CELL: THE BASIC OF LIFE

• The cell is the basic unit , structure and function an all living things.

• Organisms are made up of one or more cell.

• All cells are enclosed by a plasma membrane to separate them from their external environment

• Cell contain genetic material

• Most cells are small

DIFFERENT PARTS OF THE CELL

3 major parts:

1. nucleus – serves as the control center of the cell or the brain of the cell, 2. cytoplasm – which contains the organelles, and

3. cell membrane – the outer boundary of the cell and is responsible for the regulation of the passage of the materials to and from the cell.

Why is the nucleus called the brain of the cell?

NUCLEUS• Contains the genetic information that

directs all activities of a living cell • The most easily seen organelle inside a

eukaryotic cell; it is the largest organelle.• Eukaryotic cell posses a single nucleus

( red blood cells of the mammals lose their nucleus when they mature, causing them to stop growing in size and inability to divide.)

Do you want to know where

proteins are made inside the cell?

RIBOSOMES

• It is found in both prokaryotes and eukaryotes• It is serve as the site of protein

synthesis ( the assemble of amino acids into protein) mRNA

ENDOPLASMIC RETICULUM

It is a system of small, parallel, and flattened cavities lined with a thin membrane

2 Kinds of ER1. Smooth ER2. Rough ER

• It organizes the synthesis of lipids and other biosynthetic activities

• It is synthesize protein to exported

What happens to the cell after it is synthesized from the rough ER?

GOLGI COMPLEX• Is a stack of flattened cavity.• After receiving the newly formed protein

from ER, attaches either a short sugar chain to the protein. Forming a Glycoprotein or polysaccharide bound to a lipid forming glycolipid.

• When the need for protein arises, the stored substances peels off from the Golgi body to be transported to the different destinations.

• The packaging and delivery center of the cell.

Do you want to know how cells digest their

food?

LYSOSOMES• Digestion takes place inside the

lysosomes, removing harmful materials outside the cytoplasm or using digested substance for synthesis of other cellular materials.

• Called as the suicide bag of the cell.

AUTOLYSIS – causing the death of the cell when the cells are already old by releasing enzymes

Where do cells get there energy to

perform delicate tasks?

MITOCHONDRION( plural mitochondria)

• Is the cite for cell respiration

• It release stored energy of the food molecules by transforming glucose to ATP (Adenosine TriPhospate)

• These organelle is double walled• POWERHOUSE of the cell.

CELL MEMBRANE• It is a double layered structure, which

encloses the cell.• Made up of Phospholipid bilayer and

proteins that can be very Rigid.• Selectively permits some molecules ;

oxygen, carbon dioxide, glucose , amino acids, mineral, nutrients, and water.

How can a cell protect itself from the external

conditions outside?

Other organelles found only in plant cell:

CELL WALL – provides rigidity to plants. It is made up of the protein cellulose

- it is also responsible for the turgidity ( when it is filled with cell sap)CHLOROPLAST – site for food production in plant cell, contain Green Pigment called ( CHLOROPHYLL)- It traps light for photosynthesis. Light Energy Chemical EnergyVACOULE – Temporary storage of the cell like water, salts, amino acids, and protein. It also provides turgidity of plants and as dumping area for toxic substance.

UNICELLULAR AND MULTICELLULAR

MULTI CELLULAR – Organisms that are compose of thousands of millions of cells.

ex. animals and plants

UNICELLULAR – Made up only of one cell all throughout their existence.

ex. Bacteria and yeast

Comparison Between A Prokaryotic Cell And A

Eukaryotic CellProkaryotes Eukaryotes

Nucleus Not distinct DistinctDNA Disperse

throughout the cell

Localized inside the nucleus

Nuclear Membrane

None Present

Organelles Few ManyRibosomes Small Large

Cell Division Binary Fission Mitosis or Meiosis

Useful Technologies Using Cellular Structures

And Functions1.Reproductive Cloning – dolly the clones

sheep, in a process called “Somatic Cell Nuclear Transfer” (SCNT)

2.Liposome, with great Therapeutic Value.

3.Cytoskeleton, Useful for Origins of Cancer.

4.Studies on Smooth ER Ushers Antidote for Ethylene Glycol Poisoning.

5.British Scientists Find Prostate Cancer Gene.

QUESTIONS?