Animal Cells

OBJECTIVES

DISCUSSIONEVALUATION

OBJECTIVESAt the end of the discussion, the students will be expected to:

i. Identify the different parts of an animal cell and know their functions. ii. Draw and label its parts after the discussion.iii. Give the importance in knowing the different parts of an animal cell.

Discovery of the Cell? 1665, Robert Hooke examined thin slices of cork and other plant materials contained microscopic compartments; named it cells

Anton Van Leeuwenhoek made further observations of the cells of plants , animals and microorganisms

Matthias Schleiden –all plants are composed cells Theodore Schwann– all animals are composed of cells

Rudolf Virchow- proposed the cell theory

1840,Purkinje named the cell contents protoplasm

1.Nucleolus2.Nucleus3.Ribosome 4.Vesicle5.Rough endoplasmic reticulum6.Golgi apparatus (or "Golgi body")7.Cytoskeleton8.Smooth endoplasmic reticulum9.Mitochondrion10.Vacuole11.Cytosol 12.Lysosome13.Centrosome14.Cell membrane

Components of a Typical Animal Cell

1. Nucleolus largest structure in the nucleus consists of nucleolar organizers, ribosomal RNA, and proteins

Function:primarily serves as the site of ribosome synthesis and assembly..

2. Nucleus

Notable structure within the cell The genetic control centre of the cell -chromatin(network of dark-staining threads) Surrounded by nuclear envelopeFunction: directs cell division control protein synthesis and many of the metabolic activities of the cell

The border of the cell About 8 nm thick A semi-permeable membrane Composed of proteins and lipids

Unit membrane Model-tripartite arrangement of the plasma membrane (protein-lipid-protein)

Cell Membrane

Fluid Mosaic model- protein molecules penetrated into the lipid layers and not continuous in on the surface of lipid

Cell Membrane

Function: It supports and protects the cell. Regulates the movement of material in and out of the cell

Facilitated diffusion- scattering of particles, from high concentration to lower concentration

Active transport- process resembling facilitated diffusion in that it involves association of molecules to be transported with a membrane area of low concentration to high concentrationPinocytosis- engulfing of particles

Cell Membrane

A large interconnecting membrane of tunnelsContinuous with the nuclear envelope

Two types:1. Rough Endoplasmic Reticulum - network of interconnected flattened sacs - is studded with ribosomesFunction: to make protein( secretory protein),to make more membrane channelling products both to the outside of the cell, via the membrane

Endoplasmic Reticulum

2.Smooth Endoplasmic Reticulum network of interconnected

tubules lack of ribomes Function: Synthesizing and

secreting of certain steroid hormones, enzymes of carbohydrate metabolism, and enzymes of lipid synthesis.

Endoplasmic Reticulum

Named from Camillo Golgi, n Italian biologist and physician

A series of from 3 to 20 parallel flattened sacs closely stacked together, cisternae

End of the sacs bud off various vesicles

Function: receives and modifies and packages the substances manufactured by ER,

Golgi Body

Are spherical to rod- shaped structures from 0.2 to 7µm; a doubled layer membrane

Cristae( complex folding of inner membrane)

Mobile structures, capable of changing their shapes

“powerhouse of the cell”Function: produced energy in the form of ATP

Mitochondrion

Produced by the rough ER and the Golgi apparatus.

Two Greek words, “breakdown body”

Are membrane bound, dense-appearing structures that contain enzymes( acid hydrolases)

Function: acts as waste –disposal units, digesting and removing foreign material

“suicidal bag”

Lysosomes

enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution

Function:Digestion; storage of chemicals, cell enlargement; water balance

Vacuoles

Tiny spherical structure Bodies in which the amino

acids are bound together Site of protein synthesis

Ribosomes

quite near the nucleus Inside of it is the centriole Centriole— pair of small rod –like structure there are attached microtubules in the wall Function:active in the process of cell division( mitosis)

Centrosome

Cytoskeleton an intracellular matrix

that supports cell shape and function

The matrix is a dynamic structure composed of three main proteins

Has three components: microfilaments microtubules intermediate filaments, Actin filaments are in red,

microtubules are in green,

Microtubules- tiny cylindrical elements of animal cells about 20 to 25 nm in diameter composed of tubulins function: provide rigidity and

shape in one area Tracts for organelle movement within

the cell Basis of ciliary and flagellar

movement

Microtubules in gel fixated cell

Cytoskeleton

Microfilaments-smaller than microtubules ranging in diameter from 4 to 7 nm

Solid helical rods composed of actin

Function:providing motive force for cell contraction amoeboid movement, and possibly intracellular transport

Cytoskeleton

Cytoplasm

Protoplasm that surrounds the nucleus

A semi-liquid substance that composes the foundation of the cell

Within the cytoplasm are a number of different organelles

Identify and label its parts

References:

Biology: Concepts and Connections by Campbell, Mitchelle and Reece

General Zoology by Storer,Usinger, StibbensE-biology: The Next Generation by Santos, Danac and

OcampoBiology for non-sience majors by Reyes et. AlWikipedia.orgEnchanted Learning.com