CELL STRUCTURE

Andrijana Kološa 2nd year, 2013/2014School of Medicine

Starting point

living organisms cells

smaller pieces proteins and organelles

larger pieces tissues, organs and organ systems

About cellcell – basic structural and

functional unit  tissues, organs

each cell different function

every cells reproduction, growth and development

One name, many types

TYPES OF CELLS:

1) prokaryotic cells (prokaryotes): eubacteria, archeabacteria

2) eukaryotic cells (eukaryotes – unicellular, multicellular ): - plant cells - animal cells (human cells)

cells unique to each type of organism

Cell specializationmulticellular organisms

different cell types that are adapted to particular functions

major cell types – skin cells, muscle cells, neurons, blood cells, fibroblasts, stem cells

most distinct cell types arise from a single totipotent cell(a zygote) that differentiates into hundreds of different cell types

Organellesparts of cell specialized for carrying out one or more

vital functions to the organs

several types1. typically solitary (nucleus, golgi apparatus)

2. numerous (mitochondria, chloroplasts, peroxisomes, lysosomes)

cytosol – gelatinous fluid that fills cell and surrounds the organelles

Cell membraneBiological membrane – envelops the cell

separation and protection from cell’s surroundings

selectively permeable – regulates what moves in and out

made mostly from a double layer of phospholipids

other functions: cell adhesion, ion conductivity and cell signalling

Cytoskeletonit acts to organize and maintain the cell’s shape

endocytosis; cytokinesis

moves parts of the cell in processes of growth and mobility

composed of microfilaments, intermediate filaments and microtubules

Endoplasmic reticulumtransport network for molecules

targeted for certain modifications

continuous with the outer membrane of the nuclear envelope endomembrane system

SMOOTH ER – lipid, phospholipid and steroid synthesis; sarcoplasmic reticulum

ROUGH ER – ribosomes; protein synthesis

Golgi apparatuspart of endomembrane

system

packages and modifies proteins inside the cell before secretion

involved in creation of lysosomes lysosomic vesicles

lysosomes – organells containing acid hydrolases intrcellular digestion

Mitochondrion  "cellular power plants" generate

most of the cell's ATP

composed of specialized regions: outer membrane, intermembrane

space, inner membrane, cristae and matrix

its own independent genome

Nucleus "cell informaton center" houses

the ecell chromosomes

separated from cytoplasm by double membrane – nuclear envelope

DNA replication and RNA synthesis

nucleolus specialized region within nucleus where ribosome subunits are assembled.

Genetic materialDNA long-term information storage

RNA is used for information transport (mRNA)

enzymatic functions (rRNA)

adding amino acids during protein translation (tRNA)

genetic material contained in the cell nucleus and in the mitochondria

nuclear genome is divided into 46 linear DNA molecules called chromosomes

Replication

involves a single cell (mother cell) dividing into two daughter cells

prokaryotic – binary fission

eukaryotic – mitosis, meiosis

Protein synthesis

cells are capable synthesizing new proteins

two major steps: transcription and translation

Growth and metabolismprocessing nutrient molecules

two distinct divisions:

1) catabolism – cell breaks down complex molecules to produce energy and reducing power

2) anabolism – cell uses energy and reducing power to construct complex molecules

glycolysis; Krebs cycle

Movement or motilitycells move during processes – wound healing, the

immune response, cancer metastatis

three steps: 1. protrusion of the leading edge of the cell

2. adhesion of the leading edge and de-adhesion at the cell body and rear

3. cytoskeletal contraction to pull the cell foward

Resources

http://www.biology4kids.com/files/cell_main.html

http://en.wikipedia.org/wiki/Cell_(biology)

Cooper, Hausman: The Cell, A molecular approach, Sinauer Associates, 5th edition