Cell Structures

Swazi Nontobeko Mhlongo

Grade 10

Cell unit structure of life

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What is Biology?

Biology is the study of all living things

Living things are called organisms

Organisms include bacteria, protists, fungi, plants, & animals

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All Living Things Share Common Characteristics

1. Basic Unit is the Cell

2. They Reproduce

3. All Based On Universal Genetic Code (DNA)

4. Grow & Develop

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Characteristics of Organisms

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All Organisms are made of Cells

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Facts About Cells

Cells are the smallest living unit of an organism

All cells contain living material called cytoplasm

All cells are surrounded by a cell membrane that controls what enters & leaves the cell

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More Cell Facts More complex cells are called

Eukaryotes

These cells DO have a nucleus and membrane-bound organelles

Plants, animals, protists, & fungi are examples

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Number of Cells

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Organisms may be:• Unicellular – composed of one cell• Multicellular- composed of many cells that may organize

Types of CellsTypes of Cells

Prokaryotes - Bacteria

Eukaryotes – Animals, plants, fungi, and protists.

10Eukaryotic CellProkaryotic Cell

Prokaryotes

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Nucleoid region contains the DNA

•Cell membrane & cell wall

• Contain ribosomes (no membrane) to make proteins in their cytoplasm

Two Types of Reproduction

Sexual Reproduction

Involves 2 parents

Egg fertilized by sperm to make a ZYGOTE

Offspring DIFFERENT from parents

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Cells Have a Genetic Code

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Genetic Code

DNA (deoxyribose nucleic acid) carries the genetic code for all organisms

All organisms contain DNADNA codes for the proteins

that make up cells & do all the work

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Cells Require Food & Energy

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Food RequirementsAutotrophs can make

their own foodPhotoautotrophs use

sunlight to make food (photosynthesis)

Chemoautotrophs use chemicals such as iron & sulfur as their energy

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Food RequirementsHeterotrophs can NOT

make their own foodThey must consume other

organismsHerbivores eat plantsCarnivores eat meatOmnivores eat plants &

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Basic Structure of a Cell

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Eukaryotic Cell

Contain 3 basic cell structures:

NucleusCell MembraneCytoplasm with

organelles

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Golgi Bodies Stacks of Stacks of flattened flattened

sacssacs Have a shipping Have a shipping

side & a receiving side & a receiving sideside

Receive & Receive & modify modify proteinsproteins made by ERmade by ER

Transport vesiclesTransport vesicles with modified with modified proteins pinch off proteins pinch off the endsthe ends 20

Transport vesicle

Lysosome Contain digestive Contain digestive

enzymesenzymes Break down food Break down food

and worn out cell and worn out cell parts for cells parts for cells

Programmed for Programmed for cell death (lyse & cell death (lyse & release enzymes to release enzymes to break down & break down & recycle cell parts)recycle cell parts)

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Nucleolus Cell may have Cell may have 1 1

to 3to 3 nucleolinucleoli Inside nucleusInside nucleus Disappears when Disappears when

cell dividescell divides Makes ribosomes Makes ribosomes

that make that make proteinsproteins

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Smooth & Rough Endoplasmic Reticulum

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Smooth ER lacks ribosomes & makes proteins USED In the cell

Rough ER has ribosomes on its surface & makes proteins to EXPORt

In Animal Cells:In Animal Cells:

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Active cells like muscles have more mitochondriaBurn sugars to produce energy ATP

Mitochondria

Cell or Plasma MembraneCell or Plasma Membrane

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Living layerControls the movement of materials into and out of the cell

Selectively permeable

Cell membrane

Cell WallCell Wall

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Nonliving layerGives structure and shape to plant and bacterial cells

Cell wall

Cytoplasm of a Cell Cytoplasm of a Cell

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Jelly-like substance enclosed by cell membrane

Provides a medium for chemical reactions to take place

Cytoplasm

Control Organelle

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Controls the normal activities of the cell

Contain the DNABounded by a nuclear membrane

Contains chromosomes

Nucleus

Plant CellPlant Cell

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Dead layerLarge empty spaces present between cellulose fibers

Freely permeable

Cell wall

Plant CellPlant Cell

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Protect and support the enclosed substances (protoplasm)

Resist entry of excess water into the cell

Give shape to the cell

Cell wall

Plant Cell OrganellesPlant Cell Organelles

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Have a large central vacuole

Surrounded by tonoplast

Contains cell sapSugars, proteins,

minerals, wastes, & pigments

Vacuole

Animal cellAnimal cell

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mitochondrion

nucleus

glycogen granule

cell membrane

cytoplasm

No cell wall or chloroplastStores glycogen in the cytoplasm for food energy

vacuole

Animal Cell Organelles

Near the nucleus

Paired structures

Help cell divide

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There are different kinds of There are different kinds of plant cellsplant cells

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Onion Epidermal Cells

Root Hair Cell

root hair

Guard Cells

Levels of OrganizationLevels of Organization

CELLS (muscle cells,nerve cells)TISSUES (muscle, epithelium)ORGANS (heart, lungs, stomach)

SYSTEMS (circulatory system)ORGANISM (human)

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There are different kinds of There are different kinds of “animal” cells“animal” cells

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white blood cell

red blood cell

cheek cellssperm

nerve cell

muscle cell

Amoeba

Paramecium

TissueTissue

A group of similar cells to perform a particular function

Animals : epithelial tissue, muscular tissue, nervous tissue, and connective tissue

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Similarities between plant cells Similarities between plant cells and animal cellsand animal cells

Both have a cell membrane, ribosomes, cytoplasm, and DNA

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Both share many organelles,

including mitochondria

More Differences between Plant More Differences between Plant Cells and Animal CellsCells and Animal Cells

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Animal cells Plant cells

Vacuoles small or absent

Glycogen as food storage

Nucleus at the center

Large central vacuole

Starch as food storage

Nucleus near cell wall

The Structures of a Leaf (Plant Organ)

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Stoma

Air Space

Spongy Mesophyll Cell

Chloroplast

Palisade Mesophyll Cell

The Structures of a Heart (Animal Organ)

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OrganOrgan

Different tissues group together to carry out specialized functionsHeart : consists of muscles,

nervous tissue and blood vessels

Leaf : consists of epidermis, mesophyll and vascular tissue

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References

This presentation is a mashup of 3 different sources. They are:

Nardella .M.(2010) Cell structure

http://www.slideshare.net/mnardell103/cell-structure-5702506

Accessed 05 March 2014

Mcnewbold. S. (2012) Cell structure

http://www.slideshare.net/mcnewbold/cell-structure-11143207

Accessed 05 March 2014

Tas11244 .v. (2011) Characteristics of lifeii

http://www.slideshare.net/tas11244/characteristics-of-life-ii

Accessed 05 March 2014

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