Cell Structure & Cell Structure & OrganisationOrganisation

Chapter OutlineChapter Outline(a) identify cell structures (including organelles) of

typical plant and animal cells from diagrams, photomicrographs and as seen under the light microscope using prepared slides and fresh material treated with an appropriate temporary staining technique:

• chloroplasts• cell membrane• cell wall• cytoplasm• cell vacuoles • nucleus

Chapter OutlineChapter Outline(b) identify the following organelles from diagrams

and electronmicrographs:• mitochondria• ribosomes

(c) state the functions of the organelles identified above

(d) compare the structure of typical animal and plant cells

Chapter OutlineChapter Outline(e) state, in simple terms, the relationship between

cell function and cell structure for the following:• absorption – root hair cells• conduction and support – xylem vessels• transport of oxygen – red blood cells

(f) differentiate cell, tissue, organ and organ system

What is a cell?What is a cell?

• Building blocks of life

• Simplest units of life

• Chemical reactions in the cell keeps us alive

CellsCells

White Blood CellsRed Blood Cells

CellsCells

Embryonic Stem Cells

Other Examples of CellsOther Examples of Cells

Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

CellsCells

What does a cell consists of?Each living cell consists of living material called protoplasm.

Protoplasm:• Water makes up 70% of protoplasm• Proteins• Carbohydrates• Fats

ProtoplasmProtoplasm

1) Cell Surface Membrane

2) Cytoplasm

3) Nucleus

Cell Structures in Plant Cell Structures in Plant and Animal Cellsand Animal Cells

• nucleus• cytoplasm• cell membrane• cell wall• cell vacuoles • ribosomes• mitochondria• chloroplasts

Animal and Plant CellsAnimal and Plant Cells

Animal Cell Plant Cell

Cell Structure and Function: http://lgfl.skoool.co.uk/keystage3.aspx?id=63

Animal CellAnimal Cell

Animal CellAnimal Cell

Cell Surface MembraneCell Surface Membrane• Surrounds the cytoplasm of the cell

• Partially permeable membrane

– Allows some substances but not all to move in and out of the cell

NucleusNucleus• Surrounded by a membrane

called the nuclear envelope• Contains one or more

nucleoli • Contains chromatin

Functions of the nucleus:

1. Controls cell activities such as cell growth and the repair of

worn-out parts

2. Essential for cell division

Nucleolus

CytoplasmCytoplasm• Between the cell surface membrane and the nucleus

• Contains enzymes and organelles

Organelles in the CytoplasmOrganelles in the Cytoplasm

• Mitochondria

• Ribosomes

• Chloroplasts (only in plant cells)

• Cell vacuoles

MitochondriaMitochondria• Aerobic respiration occurs in the mitochondria• Energy production• Energy used to perform cell activities such as

growth and reproduction

RibosomesRibosomes• Required for protein synthesis in the cell

Vacuoles in Animal CellsVacuoles in Animal Cells

• A vacuole is a fluid-filled space enclosed by a membrane

• Animal cells have many small vacuoles that contain water and food substances such as proteins and carbohydrates

Label and identify the diagramLabel and identify the diagram

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AB

C

D

F

E

Plant CellPlant Cell

Plant Cells: http://lgfl.skoool.co.uk/keystage3.aspx?id=63

Plant CellPlant Cell

Differences Between Animal Differences Between Animal and Plant Cellsand Plant Cells

Animal Cells Plant Cells

Cell wall absent Cell wall present

Chloroplasts absent Chloroplasts present

Vacuoles are small, temporary in animal cells

Vacuoles are large, sap-filled in plant cells

Cell WallCell Wall• Surrounds the cell surface

membrane• Cell wall is made of

cellulose• Protects the cell from injury• Gives the plant cell a fixed

shape• Cell wall is fully permeable

ChloroplastsChloroplasts

• Found only in plant cells

• Chloroplasts contain a green pigment called chlorophyll

• Chlorophyll is essential for photosynthesis, the process by which plants make food

Vacuoles in Plant CellsVacuoles in Plant Cells

• Plant cells usually have a large central vacuole which contains a liquid called cell sap

• Cell sap contains dissolved substances such as sugars, mineral salts and amino acids

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Label and identify the diagramLabel and identify the diagram

A

B

C

F

D

E

Specialised CellsSpecialised Cells

Red Blood Cell

Root Hair Cell

Nerve Cell

Sperm Cell

Egg Cell

Cell DifferentiationCell DifferentiationThe process by which cells develop special structures or lose certain structures to enable them to carry out specific functions.

Hence, cells become differentiated to form specialised cells.

The structure of each cell is adapted to perform the specific functions of the cell.

Cell DifferentiationCell Differentiation

How is cell structure How is cell structure related to cell function?related to cell function?

1) Red Blood Cell

Cell Structure Adaptation to Function

Contains haemoglobin Haemoglobin transports oxygen from the lungs to all parts of the body.

No nucleus Carry more haemoglobin which leads to increased transport of oxygen.

Circular biconcave shape Increased surface area to volume ratio of the cell. Hence, increased transport of oxygen.

How is cell structure How is cell structure related to cell function?related to cell function?

Cell Structure Adaptation to Function

Long hollow tubes (no protoplasm)

Enables water to move easily through the lumen.

Lignified walls Lignin strengthens the walls and prevents the xylem vessels from collapsing.

2) Xylem Vessel

How is cell structure How is cell structure related to cell function?related to cell function?

Cell Structure Adaptation to Function

Long and narrow Increased surface area to volume ratio of the cell which leads to increased absorption of water and mineral salts from the soil.

3) Root Hair Cell

Specialised Plant and Animal Cells: http://lgfl.skoool.co.uk/keystage3.aspx?id=63

How do cells How do cells work together in work together in a multi-cellular a multi-cellular

organism?organism?

Organisation in Living Things: http://lgfl.skoool.co.uk/keystage3.aspx?id=63

TissueTissueA tissue is a group of similar cells which work together to perform a specific function.

Examples of tissues:• Muscle, the lining of the intestine, the lining of the lungs, phloem, root hair tissue

Connective Tissue

OrganOrganDifferent tissues may be combined together to form organs.

An organ is a structure made up of different tissues working together to perform a specific function.

Examples of organs:• Heart, lung, brain, leaf, root

Lungs

An organ is a structure made up of different tissues working together to perform a specific function.

Organ SystemOrgan SystemOrgans work together to form organ systems.

Various systems work together to make up the entire organism.

Examples of organ systems:• Circulatory system, respiratory system, digestive system, nervous system and

reproductive system

Circulatory System

Organ SystemsOrgan Systems

SystemSystem OrgansOrgansDigestive Esophagus

Stomach

Small intestine

Large intestine

Respiratory Trachea

Lungs

Organs work together to form organ systems.

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Q1. Write out the order of cell organisation within an organism.

Q2. Give an example of an animal system with the order of cell organisation stated above.

Organism

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Q1. Write out the order of cell organisation within an organism.

• Intestinal cell intestinal muscle small intestine digestive system human

• Nerve cell nerve tissue eye sensory system bird

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Q2. Give an example of an animal system with the order of cell organisation stated above.