Bacteria & Yeast cells LO: Be able to label the parts of bacterial and yeast cells and their (approximate) size Describe how they differ from plant, animal.

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Presentation on theme: "Bacteria & Yeast cells LO: Be able to label the parts of bacterial and yeast cells and their (approximate) size Describe how they differ from plant, animal."— Presentation transcript:

1 Bacteria & Yeast cells LO: Be able to label the parts of bacterial and yeast cells and their (approximate) size Describe how they differ from plant, animal and fungal cells Understand how structure is related to function for a range of specialised cells Understand the keywords: slime capsule, plasmids, flagella

2 Bacterial Cell What are bacteria? Bacteria are single celled organisms. They do not have DNA in a membrane bound nucleus – so are called prokaryotes (from the Greek meaning before nucleus). Their genetic material is in a long strand. Sometimes the genetic material is found in circles called plasmids – which many contain genes for antibiotic resistance.

3 1 μm http://www.cellsalive.com/cells/bactcell.htm#surfacehttp://www.cellsalive.com/cells/bactcell.htm#surface - click to find out about the function of each cell part Note: not all bacteria have a flagellum. What do you think the function of the flagellum is?

4 Do you know your units? A micrometer, abbreviated as um and sometimes known as a micron, is equal to one millionth of a meter. It would take about 13,000 bacteria lying end to end to stretch the length of one inch. A micrometer, abbreviated as um and sometimes known as a micron, is equal to one millionth of a meter. It would take about 13,000 bacteria lying end to end to stretch the length of one inch. Under a light microscope, bacteria are so small that they are usually visible only as tiny dots.

5 Bacteria: staphylococcus aureus (commonly referred to as strep as in ‘Strep throat infections) A pair of Staphylococcus aureus have gone through 2 cell divisions, producing a pair of tetrads. Cell division in this and other bacteria can occur every 20 to 30 minutes.

6 E.Coli Escherichia coli (E. coli ) are very common intestinal inhabitants. Some can be dangerous in food and water supplies. Most newsworthy are life-threatening infections from eating undercooked food causing food poisoning.

7 Helpful bacteria

8 ‘Friendly’ bacteria live in your body Certain types of bacteria live in the intestines. They help in digestion and in destroying the harmful organisms. Certain bacteria help break down lactose in the digestive tract. Some bacteria present on the skin protect us from the spread of certain fungus. There are many bacteria that live inside the mouth, nose, throat, and intestines of humans and animals. These get a place to live and feed while keeping other harmful microbes from taking up residence. Certain bacteria may work harmoniously with our immune system. There are some bacteria which are helpful to release many useful vitamins such as vitamin B and vitamin K. The most important task that stomach bacteria do is to maintain normal pH level or acid level of human stomach.

9 So not all bacteria are bad…….. Probiotics or 'friendly' beneficial bacteria : promote good digestion boost immune function, aid in the breakdown of proteins and fats in food, help to absorb vitamins, minerals & amino acids and increase resistance to inflammation and infection by inhibiting the growth of harmful bacteria

10 Harmful bacteria Certain bacteria that cause illness act as pathogens and cause tetanus, typhoid fever, pneumonia, syphilis, cholera, food-borne illness and tuberculosis. Streptococcus bacteria may cause small infections like strep throat and some serious diseases like pneumonia, some may be fatal. Campylobacter is a group of bacteria that can create illnesses in humans and is a common cause of food poisoning. Harmful bacteria in food cause botulism, which can cause paralysis or even death if even one-millionth of the bacterium is ingested. Yersinia pestis or bubonic plague, is a rod-shaped type of bacterium Antibiotics are widely used to kill harmful bacteria. Washing hands with antiseptic soap will kill the bacteria. Food for thought…. ‘while good bacteria can survive without us, we cannot survive without good bacteria’

11 Another useful micro-organism- The Yeast Cell Approx. 3-4 µm Is a yeast cell bigger or smaller than a bacterial cell?

12 Yeast cells reproduce asexually This picture shows a yeast cell reproducing – try to explain what you think is happening at each stage: 1 2 3 1.Parent Yeast cell makes a copy of its nucleus 2.Copied nucleus moves to the bud 3.Bud pinches off to leave 2 identical cells called daughter cells 1 2 3

13 Yeast cell key points Single celled organisms Use aerobic respiration when oxygen is in plentiful supply Use anaerobic respiration when there is not much oxygen, producing ethanol (alcohol) and carbon-dioxide Used for bread making, in marmite, Reproduce asexually by budding In what ways is a yeast cell similar/different to a bacterial cell?

14 Cell Wall Vacuole Mitochondria Septum Nucleus Cell membrane Cytoplasm ANIMAL CELL PLANT CELLBACTERIAL CELL Cell Membrane Nucleus Cytoplasm Mitochondria Cell Wall Cell Membrane Nucleus Vacuole Chloroplast Cytoplasm Mitochondria Flagellum Cell Wall Cytoplasm Cell Membrane Nucleoid Pili Defining Features: *No cell wall *Mitochondria *No chloroplasts *Animal cells move! Defining Features: *Cell Wall of cellulose *Mitochondria *Chloroplasts *Vacuole Defining Features: *Cell Wall *No mitochondria *Nucleoid instead of nucleus *Some have pili *Some have flagellum *No chloroplasts Defining Features: *Cell Wall of chitin *Septum (separates cells, but has pore) *Several nuclei *Mitochondria *Vacuole *Apical, polarised growth This document may be copied freely for educational purposes only. All rights reserved for commercial use. Text © Ruth Townley 2005; design and production © David Moore 2005. FILAMENTOUS FUNGAL CELL FC04 Revision Compare the similarities and differences between Fungal, animal, plant and bacterial cells.

15 Specialised cells LO: Be able to recognise specialised cells and relate their structure to their function Can you name these specialised cells?

16 How are they adapted to their particular job? Cone cells (from the human eye) Human Ova (egg) cell & sperm Plant root hair cells Fat cells

17 Specialised cells – structure & function

18 Other specialised cells


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