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Chapter 2 Cells.

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Presentation on theme: "Chapter 2 Cells."— Presentation transcript:

1 Chapter 2 Cells

2 Ch 2.1 – Cell Structure A. Cell size & shape
1. Directly related to cell function

3 B. Cell Organization 1. Cell Membrane – protective layer around outside of all cells a) flexible b) controls substances moving into and out of the cell Cell Membrane

4 2. Cell Wall – structure located around the
outside of the cell membrane in some cells a) found around cells of plants, algae, fungi and some bacteria b) much thicker than cell membrane and made of cellulose to provide extra protection Cell Membrane Cell Wall

5 3. Cytoplasm – gelatin like substance inside the cell membrane
a) Has cytoskeleton – internal structure to help keep the cell’s shape b) Contains organelles – tiny structures each with their own job to help with the cell’s life processes Cytoplasm

6 4. Nucleus – control center of the cell
a) organelle that contains a cell’s hereditary material (DNA) b) DNA provides instructions for everything the cell does Nucleus

7 C. Two types of cells 1. Prokaryotic cells – simpler than most; lack a nucleus and organelles a) example: bacteria cells 2. Eukaryotic cells – contain a nucleus and organelles a) example: plant & animal cells

8 D. Other Organelles 1. Energy processing organelles a) Chloroplasts - green organelles in plant and algae cells that make food; where photosynthesis takes place Chloroplasts

9 b) Mitochondria – the powerhouse of the
b) Mitochondria – the powerhouse of the cell; release energy from food; found in plant and animal cells Mitochondria

10 2. Manufacturing organelles
a) Ribosomes – make proteins -some float freely in the cytoplasm, others are attached to the endoplasmic reticulum Ribosomes (Dots)

11 3. Transporting organelles
a) Endoplasmic Reticulum (ER) - series of membranes to move substances around the cell -Rough ER – ribosomes attached -Smooth ER – no ribosomes attached ER (channels)

12 4. Packaging organelles a) Golgi bodies – package substances into vesicles to move things around the cell or out of it to other parts of the body Golgi Bodies (channels)

13 5. Storage organelles a) Vacuoles – temporary storage places for food, water and waste - large in plant cells - small in animal cells Vacuoles

14 6. Recycling organelles a) Lysosomes – break down cell waste products

15 Organization of Living Things
1. All living things are made of cells 2. Cells working together makes a tissue 3. Tissues working together make an organ 4. Organs working together make an organ system 5. Organ systems working together make up an organism

16 Ch 2.2 – Viewing Cells A. Magnifying Cells
1. Early Microscopes – lenses made images larger but not always clear a) first microscope made in 1500’s by reading glass maker who put two magnifying glass lenses on top of each other in a tube

17 b) In the mid-1600’s Antonie van Leeuwenhoek created a microscope with a glass bead powerful enough to see tiny creatures in pond water that he called “beasties”

18 c) During the late 1600’s microscope technology improved as scientists used these inventions to explore the world in a new way d) In 1665, Robert Hooke was the first person to discover and coin the term “cells” after examining a thin slice of cork under his microscope

19 e) In the 1830’s Matthias Schleiden determined that all plants were made of cells
f) Soon after Theodor Schwann concluded that all animals were made of cells

20 2. Modern Microscopes – use lenses to bend light
a) A simple light microscope has one lens while a compound light microscope has multiple lenses

21 b) Magnification – tells how many times an image has been magnified from its original size c) For compound microscopes, power of the eyepiece multiplied by the power of the objective lens determines an objects total magnification

22 3. Electron Microscopes – more powerful than lens microscopes
a) use electron beams to produce photographs or electronic images of objects magnified up to one million times their actual size

23 B. Development of the Cell Theory
1. The cell theory resulted from many scientists’ observations and conclusions of microscope studies 2. It states: -The basic unit of organization is the cell -All organisms are composed of one or more cells -New cells come from old cells through cell division

24 Ch Viruses A. Virus – a nonliving strand of hereditary material surrounded by a protein coating

25 B. Virus multiplication – viruses can make copies of themselves only inside a living host cell
1. Active virus – immediately makes the host cell create new viruses which kills the host cell when it bursts a) causes illness soon after an organisms body is infected b) ex: the common cold & influenza

26 2. Latent virus – hides inside the host cell for a period of time before it starts creating new viruses and destroying it a) The virus’ hereditary material becomes part of the host cell’s hereditary material so that as the host cell divides an organism’s body begins to have more cells that contain the viral DNA b) Latent viruses eventually become active viruses and then destroy the host cells c) ex: HIV virus & herpes viruses

27 C. Virus effects on organisms
1. Most infect only specific kinds of cells 2. Often carried to the host through the air 3. The virus and host must “fit” together exactly to begin a viral infection 4. Bacteriophages – viruses that attach to infect bacteria cells

28 D. Fighting Viruses 1. Vaccines – made of weakened virus particles which allow cells to fight off viruses before they attack and take over

29 2. Treating viral diseases
a) Antibiotics are not effective treatments for viral infections (they fight bacterial infections) b) Antiviral drugs can treat the symptoms of a viral illness but not the disease c) Once the bodies immune system combats the viruses to reverse the illness, the cells remember this so that the same virus cannot be contracted twice

30 E. Gene Therapy – researchers studying good uses for viruses to replace defective hereditary material with normal hereditary material


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