华中农业大学：《食品微生物学》课程PPT教学课件（Food Microorganism）Chapter 2 Cell Biology

Chapter 2 Cell Biology

Chapter 2 Cell Biology

2.1 Overview of the structure of microbial cells 2.2 Procaryotic cell wall 2.3 Cytoplasmic membrane 2.4 Cellular genetic information 2.5 Cytoplasmic matrix – Ribosome and Inclusions 2.6 Components external to the cell wall 2.7 Bacterial endospores 2.8 Comparison of the prokaryotic and eukaryotic cell Chapter outline

2.1 Overview of the structure of microbial cells 2.2 Procaryotic cell wall 2.3 Cytoplasmic membrane 2.4 Cellular genetic information 2.5 Cytoplasmic matrix – Ribosome and Inclusions 2.6 Components external to the cell wall 2.7 Bacterial endospores 2.8 Comparison of the prokaryotic and eukaryotic cell Chapter outline

A procaryotic cell A eucaryotic cell Overview of cell structure

A procaryotic cell A eucaryotic cell Overview of cell structure

3. Their cell wall almost always contain the complex polysaccharide peptidoglycan The prokaryotic cell 1. Their genetic material (DNA) is not enclosed within a membrane and they lack other membrane – bounded organelles 2. Their DNA is not associated with histidine 4. They are very small!!

3. Their cell wall almost always contain the complex polysaccharide peptidoglycan The prokaryotic cell 1. Their genetic material (DNA) is not enclosed within a membrane and they lack other membrane – bounded organelles 2. Their DNA is not associated with histidine 4. They are very small!!

Size: Most bacteria fall within a range from 0.2 to 2.0 um in diameter and from 2 to 8 um in length A rod-shaped prokaryote is typically about 1-5 micrometers (μm) long and about 1 μm wide Microorganisms in general are very small and are completely invisible to the naked eye. A cyanobacterium 8 x 50 um

Size: Most bacteria fall within a range from 0.2 to 2.0 um in diameter and from 2 to 8 um in length A rod-shaped prokaryote is typically about 1-5 micrometers (μm) long and about 1 μm wide Microorganisms in general are very small and are completely invisible to the naked eye. A cyanobacterium 8 x 50 um

size comparison of microorganisms Meters Visibility scale Relative size of Microbes Prokaryotes Eukaryotes Viruses Naked eye Light microscope Electron microscope

size comparison of microorganisms Meters Visibility scale Relative size of Microbes Prokaryotes Eukaryotes Viruses Naked eye Light microscope Electron microscope

a cell increases in size, its surface area – to – volume ratio decreases Surface area and volume relationships in cells

a cell increases in size, its surface area – to – volume ratio decreases Surface area and volume relationships in cells

spirallum Shape: Bacteria have a few basic shapes spherical coccus Rod-shaped bacillus

spirallum Shape: Bacteria have a few basic shapes spherical coccus Rod-shaped bacillus

• The cell wall of the bacterial cell is a complex, semi-rigid structure that is responsible for the characteristic shape of the cell. The cell wall surrounds the underlying, fragile plasma (cytoplasmic) membrane and protects it and internal parts of the cell from adverse changes in the surrounding environment. • Almost all prokaryotes have cell walls. Prokaryotic cell wall

• The cell wall of the bacterial cell is a complex, semi-rigid structure that is responsible for the characteristic shape of the cell. The cell wall surrounds the underlying, fragile plasma (cytoplasmic) membrane and protects it and internal parts of the cell from adverse changes in the surrounding environment. • Almost all prokaryotes have cell walls. Prokaryotic cell wall

Gram+ Gram￾Schematic diagram of bacterial cell walls Bacteria can be divided into two major groups, called gram-positive and gram-negative. The original distinction between gram-positive and gram-negative was based on a special staining procedure, the Gram stain

Gram+ Gram￾Schematic diagram of bacterial cell walls Bacteria can be divided into two major groups, called gram-positive and gram-negative. The original distinction between gram-positive and gram-negative was based on a special staining procedure, the Gram stain