Structure of the Cell

Greg DolgushinHarvard SIG 2013

History of Cell Theory

CITOLOGY (cito- and –logos-) – the science about the cell

Hooke, Leeuwenhoek, Schleiden, Schwann, Virchow All living things or organisms are made of cells and their products New cells are created by old cells dividing into two Cells are the basic building units of life

Basic principles of modern cell theory All known living things are made up of one or more cells

All living cells arise from pre-existing cells by division The cell is the fundamental unit of structure and function in all

living organisms The activity of an organism depends on the total activity of

independent cells Energy flow (metabolism and biochemistry) occurs within cells

Cells contain hereditary information (DNA) which is passed from cell to cell during cell division

All cells are basically the same in chemical composition in organisms of similar species

Cells sizes and forms

Cells number

Human:100 trillions

Human gut: 300-1000 types of

bacteria ~1015 of bacteria:

ten-fold more than human cells

Cell types

Eucariot and ProcariotPresence

of nucleous

Animal and PlantKind

Somatic and GermType

Structure Eucariot ProcariotLysosomes Yes NoVacuoles Yes NoFlagellums and cilia In all except higher plants In some bacteria

Chloroplasts In some plant cells NoMicrotubules Yes No

Cell wall In plants and fungi Yes

Cell membrane Yes Yes

Nucleus Yes Nuclear area, no membrane

Mitochondrions Yes No

ER Yes No

Ribosomes Yes Yes

Golgi apparatus Yes No

Eucariot and Procariot Cells

Animal Cell

Cell wall from cellulose

Cytoplasm

Vacuoles

Nucleus

Chloroplast

Plant Cell

Membrane

Mitochondrions

ER

Ribosomes

Cytoplasm and Organelles (Organoids)

Organoids - constant cell structures, that provide the functions of the cell

Plastids

Membrane No membrane

One membrane

Endoplasmic reticulum

Golgi apparatus

Lysosomes

Two membrane

Mitochondrions

Ribosomes

Cell center

Nucleus

Vacuoles

Microtubules

Flagellums and cilia

Cytoplasm – semiliquid cell’s medium, which consists of water and proteins. It moves with the speed up to 7 cм/hour

Cell membrane isultramicroscopicfilm from twomonomolecular layersof lipids and a layer ofprotein between themFunctions of membrane: Barrier Transport Protection Metabolism with cell

environment Cell-to-cell “dialog”

Cell Membrane

Nucleus components Structure Function

Nuclei membrane External and internal membrane Metabolism between nucleus and cytoplasm

Nucleoplasm Liquid with proteins Internal medium of nucleous

Nucleolus Contains DNA Synthesis of ribosomal RNA

Chromatin Contains chromosomes Genetic information

NucleusFunctions of

nucleus: Storage of

genetical information

Regulation of cell metabolism

Endoplasmic reticulum

Functions of ER: Synthesis of

proteins, lipids and carbohydrates

Storage of proteins, lipids and carbohydrates

Connection between organoids

• Lipids and carbohydrates synthesis

• Cell membrane synthesis• Transport of different

substances to the cell

• Protein synthesis• Cell membrane synthesis• Transport of different substances out of

the cell• Lysosoms, spherosomes synthesis

Ribosomes

Non-membrane fungiform structure of big and small units, which consists of RNA and proteins

Functions of ribosomes: Protein synthesis

Functions of mitochondrions:• respiratory center of the cell• adenosine triphosphate

(ATP) synthesis (due to oxidative phosphorylation) → energy support of the cell

Mitochondrions

Number in one cell - from units to several thousands All mitochondrions=chondriome

Diameter=0.5 – 1.0 micronesLength= 1 - 7-10 micrones

Modern technologiesMitochondrial genes transfer

Golgi apparatusFunctions of GA:• Storage and transport of substances,

their chemical modernization• Secretory function• Lysosomes synthesis• Lipids and carbohydrates synthesis

Camillo Golgi (1897)

Microtubulles

Structure: protein subunitsFunctions of microtubules: Cytoskeleton formation Centrioles, flagellums and cilia formation Contribute to intracellular movement

Lysosoms

Functions of lysosomes:• Protection• Heterophagy: treatment of

foreign substances, that come to the cell due pinocytosis or phagocytosis

• Intracellular digestion• Endogenic nutrition : in

condition of starvation they digest some cytoplasmic structures

• The cavities in cytoplasm• Reservoir with cell cellular

fluid, nutrients, and metabolites

• Cellular fluid – liquid with diluted sugars and mineral salts

• With vacuoles growth the cell is growing (increases in sizes)

Functions of vacuoles:• Regulation of cell’s pressure• Storage of nutrients and

metabolits

Vacuoles

They are energetic stations of the plant cell. They can transform to other kinds of plastids.

Functions: photosynthesis biosynthesis

Type of plastid Chloroplast Chromoplast Leucoplast

Colour Green Yellow, orange or red Colourless

Pigment Chlorophyll Carotin No

Function Production of organic substances

Storage of nutrients Storage of nutrients

Plastids

3 groups of elements:• Oxygen, Carbon, Hydrogen

and Nitrogen - 98% of all structure

• Potassium, Sodium, Calcium, Sulfur, Chlorine – tenth and hundredth % parts

• Microelements- hundredth and thousandth % parts

Chemical structure of the cell

Element Amount, %

Oxygen 65-75

Carbon 15-18

Hydrogen 8-10

Nitrogen 1.5-3.0

Phosphorus 0.2-1.0

Potassium 0.15-0.4

Sulfur 0.15-0.2

Chlorine 0.05-0.1

Calcium 0.04-2.0

Magnesium 0.02-0.03

Sodium 0.02-0.03

Iron 0.01-0.015

Zinc 0.0003

Copper 0.0002

Iodine 0.0001

Fluorine 0.0001

Conclusions

All alive organisms consist of cells Cell is one of structural functional and

replicative elements of alive medium Cells of all unicellular and multicellular

organisms are similar in their structure, chemical compound, basic signs of vital activity

and metabolism