Cell Processes

1. Cell Processes By: Laikin, Kelly, and Lauren

2. Cell organelles • Nucleus : The nucleus contains the DNA and controls the cells activities. • Cell Membrane : The cell membrane controls what enters and exits the cell and helps protect the cell. • Mitochondrion : The mitochondrion converts glucose into energy and is often called the powerhouse of the cell. • Vacuole : The vacuole is a membrane bound sac within a cell or tissue that stores water ,waste ,and food until they are needed or released through the cell membrane. • Ribosome : The ribosome is the site of protein synthesis. Some are found floating around the cell or attached to endoplasmic reticulum. • Endoplasmic Reticulum : The endoplasmic reticulum is a network of passageways that carries materials through the cell. • Golgi Body : The Golgi body receives materials from the endoplasmic reticulum , packages and then disperses them to other parts of the cell. • Lysosome : The lysosome contains digestive enzymes that break down food particles as well as old cell parts. • Chloroplasts : The chloroplasts are the site of photosynthesis. • Cell Wall : The cell wall is made of cellulose that helps support and protect the cell. • Cytoplasm : The cytoplasm is the jelly like substance found inside the cell that contains organelles

3. Active and Passive Transport • Passive Transport does not require energy. • Osmosis is a type of passive transport that moves water molecules across a membrane. • Diffusion is also a type of passive transport that is the movement of molecules from an area with many molecules to an area with fewer molecules. • Facilitated diffusion is a type of passive transport it helps things through the cell membrane by protein. • Active Transport requires extra energy , and is the exact opposite of Passive Transport.

4. Cellular Respiration • Cellular Respiration is the process in cells by which oxygen and glucose are used to produce energy and carbon dioxide • Cellular respiration =glucose+oxegen >carbon dioxide and water • Photosynthesis=carbon dioxide +water>glucose + oxygen • There are three stages of cellular respiration • The first stage of cellular respiration takes place in the cytoplasm of the cell, here molecules of glucose are broken down into smaller molecules . Oxygen is not involved however a small amount of energy is released • The next two stages of cellular respiration require oxygen in eukaryotes those organisms having both a nucleus and organelles these two stages occur in the mitochondria. • In cells with no nucleus bacteria and Achaea the process continues in the cytoplasm. During these stages, the smaller molecules produced in the first stage are broken down even further, which releases a great deal of energy.

5. FERMENTATION • The process in which cells brake down molecules without the use of oxygen. • Sometimes enough oxygen is not able for cellular respiration to occur. • For example, some single celled organisms live in the depths of the ocean or deep within the earths crust there is no oxygen. • The amount of energy released is much less then the amount released during cellular respiration. • There are two common types of fermentation lactic acid fermentation and alcohol fermentation. The entire process of fermentation takes place in the cytoplasm. Glucose molecules are first broken down into smaller molecules. • In lactic acid fermentation , the molecules are further broken down and yield the by product lactic acid a toxic substance to cells . This type of fermentation is preformed by some fungi and bacteria, and occasionally by the muscles in humans. • Alcohol fermentation occurs in yeast and certain kinds of bacteria. The waste products in this process are alcohol and carbon dioxide. • Both types of fermentation occur naturally in many different types of foods.

6. Mitosis There are four phases to mitosis in order : Prophase, Metaphase, Anaphase, and Telephase. • In the second stage the nucleus divides and its called Mitosis. • The first phase is called Prophase in which the duplicated DNA pair up to form chromosomes. • The second phase called Metaphase, the chromosomes line up down the middle and attach to spindle fibers. • The third phase called Anaphase, the chromosomes separate at their centromeres and move toward opposite ends of the cell. • The fourth phase is called Telephase, the chromosomes uncoil and two new nuclear membranes form and the spindle fibers disappear.

7. Meiosis • Meiosis occurs in two stages . • In meiosis one the DNA replicates to have four chromosomes in each daughter cell. Their chromatids are held together by centromeres. • When chromosomes line up down the middle in meiosis one, maternal chromosomes pair up with its similar parental. • In meiosis two the chromosomes line up down the middle as they do in mitosis. The chromatids separate at their centromeres and move to opposite sides of the cell. This results in four gametes that have 23 chromosomes each. • Meiosis is also a process of cell division, but it is different from mitosis in several ways. • In meiosis a non reproductive cell divides two times ending with four daughter cells that are not identical. • Each daughter cell is a gamete ( a mature male or female reproductive cell ) that contains only 23 chromosomes. • During sexual reproduction a male gamete fuses with a female gamete. When these two gametes combine to form one new cell their combination of chromosomes equal those found in a somatic cell.

8. Asexual reproduction • Prokaryotes, or bacteria, many protist, and even some algae and worms reproduce asexually using a process called binary fission. • Binary fission occurs when one parent cell grows about twice its normal size. After this a copy of DNA is made and the parent cell begins to split in two. • The cell membrane surrounds each half, forming two new identical cells. • Many bacteria cells complete binary fission in a couple of minutes. • Spores are another way in which bacteria fungi and some plants reproduce asexually. • Budding is a type of asexual reproduction that involves the outgrowth of a small part of the parent develops into an new organism. • Vegetative reproduction is a common type of asexual reproduction found in plants here the growth from the parent plant eventually becomes new individual plants.