Lesson 2.1Cell structure and function

Disediakan oleh:NUR SUHAIDAH SUKORSMK SANDAKAN, SABAH

Introduction

Cell Theory1. All organisms are composed of cells.2. Cells are the smallest living things.3. Cells arise only from pre-existing cells.

All cells have certain structures in common.1. genetic material – in a nucleoid or nucleus2. cytoplasm – a semifluid matrix3. plasma membrane – a phospholipid bilayer

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Animal Cells

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Plant Cells

Nucleus

Sphericalstores the genetic

material. DNA is organized with proteins to form chromatin.

Func: controls all activities of cell.

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Rough endoplasmic reticulum (RER)

Membranes that create a network of channels throughout the cytoplasm

Attachment of ribosomes to the membrane gives a rough appearance.

Synthesis of proteins to be secreted, sent to lysosomes or plasma membrane

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Smooth endoplasmic reticulum (SER)

Relatively few ribosomes attached.

Functions:-synthesis of membrane lipids-detoxification of drugs

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RER & SER

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Flattened stacks of interconnected membranes.

Packaging and distribution of materials to different parts of the cell.

Lysosome are formed through budding of vesicles.

Golgi Apparatus

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Golgi apparatus

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Lysosomes

-membrane bound vesicles -containing digestive enzymes to break down macromolecules-destroy cells or foreign matter that the cell has engulfed by phagocytosis

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Lysosomes

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Vacuoles spherical or oval shaped filled with fluid. cell sap contains sugar, salts, amino acid and waste substances. bounded by semi-permeable membrane called tonoplast.There are different types of vacuoles:

-contractile vacuole-food vacuole

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Mitochondria

Mitochondria-cylindrical shape-two layers of membrane (inner membrane is folded)

Func –site for cellular respiration.-oxidise glucose to release energy in the form of ATP.

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Mitochondria

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Chloroplasts

Chloroplasts-Disc shaped organelle bounded by two membranes.-grana are stacks in the stroma-granum contain chlorophyl

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Chloroplasts

Cell wall

Structure-rigid outer layer of plant cell-made of cellulose-permeable

Func –mantains the shape of plant cell-protects the cell from brusting-give support to the cell

CytoplasmaStructure –jelly like mediumFunc –place for biochemical reactions

CentriolesStructure –small cylindrical structuresFunc –form spindle fibers

-synthesis cilia and flagella of small organism.

Plasma Membrane

Structure-thin, semi permeable membrane.-consists of protein, phospholipids.

Function-regulates and control the movement of substances in and out of cell.

The density of certain organelles related to its function

Types of cells Function Density of certain organelles

Sperm cell To swim towards fallopian tube to fertilise the ovum

Mitochondria need to produce energy

Flight muscles insect and bird

For movement Mitochondria

Cells in meristem For growth, produce new cells

mitochondria

Palisade mesophyll cells photosynthesis Chloroplast

Liver cells Detoxification of drugs Smooth endoplasmic reticulum

Pancreatic cells Produce enzymes Rough endoplasmic reticulum, golgi