Basic Structure of a Cell 1 Introduction to

Basic Structure of a Cell 1

Introduction to Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal Cell Plant Cell Bacterial Cell 2

The Cell Theory • All living things are composed of cells. • Cells are the basic units of structure and function in living things. • New cells are produced from preexisting cells. 3

Number of Cells Organisms may be: • Unicellular – composed of one cell • Multicellularcomposed of many cells that may organize 4

Cells May be Prokaryotic or Eukaryotic § Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles §Eukaryotes include most other cells & have a nucleus and membranebound organelles (plants, fungi, & animals) 5

Prokaryotes Nucleoid region contains the DNA • Cell membrane & cell wall • Contain ribosomes (no membrane) to make proteins in their cytoplasm 6

Eukaryotic Cell Contain 3 basic cell structures: • Nucleus • Cell Membrane • Cytoplasm with organelles 7

Two Main Types of Eukaryotic Cells Plant Cell Animal Cell 8

Organelles Very small size Can only be observed under a microscope Have specific functions Found throughout cytoplasm 9

Organelles Found in Cells Examples of Organelles include: Endoplasmic reticulum (rough & smooth) – canals for movement Golgi Bodies – wrap & export proteins Nucleolus – makes ribosomes Lysosomes – digests & gets rid of wastes Ribosomes – makes proteins 10

Golgi Bodies • Stacks of flattened sacs • Have a shipping side & a receiving side; • Packaging center of the cell. Transport vesicle 11

Lysosome • Contain digestive enzymes • Break down food and worn out cell parts for cells 12

Nucleolus • Cell may have 1 to 3 nucleoli • Inside nucleus • Makes ribosomes that make proteins 13

Smooth & Rough Endoplasmic Reticulum Smooth ER lacks ribosomes & makes proteins USED In the cell Rough ER has ribosomes on its surface & makes proteins to EXPORT 14

Cell Powerhouse Mitochondrion ( mitochondria ) Rod shape Site of Cellular respiration 15

In Animal Cells: Mitochondria Active cells like muscles have more mitochondria 16

Surrounding the Cell membrane Lies immediately against the cell wall in plant cells Made of protein and phospholipids Selectively permeable 17

Cell or Plasma Membrane Cell membrane Living layer Controls the movement of materials into and out of the cell Selectively permeable 18

Cell Wall Cell wall Nonliving layer Gives structure and shape to plant and bacterial cells. 19

Cytoplasm of a Cell Cytoplasm Jelly-like substance enclosed by cell membrane. Contains organelles to carry out specific jobs 20

Control Organelle Nucleus Control center of the cell; Contain the DNA Bounded by a nuclear membrane Contains chromosomes 21

Plant Cell Organelles Chloroplast Contain the green pigment chlorophyll; Traps sunlight to make sugars (food); Process called photosynthesis 22

Plant Cell wall Protect and support the enclosed substances (protoplasm); Give shape to the cell 23

Plant Cell Organelles Vacuole Have a large central vacuole; Contains cell sap Sugars, proteins, minerals, wastes, & pigments 24

Different kinds of plant cells Onion Epidermal Cells Guard Cells root hair Root Hair Cell 25

vacuole cytoplasm Animal cell nucleus No cell wall or chloroplast Stores glycogen in the cytoplasm for food energy mitochondrion glycogen granule cell membrane 26

Animal Cell Organelles • Near the nucleus • Paired structures • Help cell divide 27

Different kinds of animal cells white blood cell Amoeba red blood cell muscle cell cheek cells sperm nerve cell Paramecium 28

Similarities cells and between plant animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria 29

Differences between plant cells and animal cells Animal cells Plant cells Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present 30

Differences between Plant Cells and Animal Cells Animal cells Plant cells Vacuole small or absent Large central vacuole Glycogen as food storage Starch as food storage Nucleus at the center Nucleus near cell wall 31

Compound Microscope • Instrument for observing small objects • Magnify images up to 2000 X their size 32

Different parts of a microscope 33

Revolving nosepiece Eyepiece Clip Body tube Coarse adjustment Fine adjustment Condenser Arm Iris diaphragm Stage Objective Mirror Condenser control knob Base 34

Levels of organization • Cells are grouped together and work as a whole to perform special functions 35

Tissue • A group of similar cells to perform a particular function – Animals : epithelial tissue, muscular tissue – Plants : vascular tissue, mesophyll 36

Organ • Different tissues group together to carry out specialized functions – Heart : consists of muscles, nervous tissue and blood vessels – Leaf : consists of epidermis, mesophyll and vascular tissue 37

The Structures of a Leaf (Plant Organ) Chloroplast Palisade Mesophyll Cell Spongy Mesophyll Cell Air Space Stoma 38

The Structures of a Heart (Animal Organ) 39

System • Several organs and tissues work together to carry out a particular set of functions in a co-ordinated way – Human : digestive, respiratory, excretory, circulatory and reproductive systems – Plant : root and shoot systems 40

Human Body Systems Examples of systems : ´ Digestive System ´ Respiratory System ´ Circulatory System ´ Nervous System ´ Reproductive System 41

Examples of a Human Body System 42

Examples of a Human Body System 43

Examples of a Human Body System Circulatory System 44

Examples of a Human Body System Nervous System 45

Levels of Organization ³CELLS (muscle cells, nerve cells) ³TISSUES (muscle, epithelium) ³ORGANS (heart, lungs, stomach) ³SYSTEMS (circulatory system) ³ORGANISM (human) 46

It’s You! 47