Homework Questions Page 14 #1,3 Page 15 #2,3,4,5 Page 18 #1-3 Page 22 #6,7 Page 26 #9,10 Page 28 #1,3,8 Page 32 #2,3 Cells and More Cells

Cells and Cell Structure Cells  The smallest unit that can perform the functions of life; there are many different types of cells even within the same organism Cells are made up of organelles; specialized structures that perform specific functions within the cell The first organelle discovered within the cell was the nucleus which is the structure responsible for controlling the overall activity of the cell The nucleus of the cell is made up of a nuclear membrane which protects the contents of the nucleus, a nucleolus which makes ribosomes which in turn synthesize proteins and nuclear pores which allow materials in and out of the nucleus

Cells and Cell Structure The fluid material between the cell membrane and the nucleus is known as the cytosol which is filled with many specialized organelles The organelles of the cell each play a role in the proper functioning of cell; a critical role of many organelles includes the production, storage or transport of proteins Proteins are essential for growth and repair of body tissues; all cells depend on proteins to carry out the life processes that keep you healthy The cytosol and organelles it contains is collectively called Cytoplasm

Animal Cell

Plant Cell

The Cell Theory 1. All living organisms are made of one or more cells 2. The cell is the basic organizational unit of life 3. All cells come from pre-existing cells

Cells and Cell Structure Some types of organelles are found in both plant and animal cells, while other types are found only in one or the other E.g. Mitochondria are found in both plant and animal cells while chloroplasts are found only in plant cells, not in animal cell Cellular Respiration is the process by which cells produce energy using glucose; this process occurs in the mitochondria of cells Refer to Figure 1.5 and 1.6 on page 12 of your text  YOU ARE RESPONSIBLE TO KNOW THE NAME AND FUNCTION OF EACH TYPE OF ORGANELLE FOUND IN BOTH AN ANIMAL AND PLANT CELL!

Genes The nucleus of the cell contains the master set of instructions that determines what each cell will become, how it will function and how long it will live  These instructions are carried by thread- like structures in the nucleus known as Chromosomes Every plant and animal species has a specific number of chromosomes in the nucleus of each cell  these chromosomes come in pairs; one from each parent when an egg and a sperm unite to form a fertilized egg E.g. Humans have 46 chromosomes (23 donated from the mother’s egg and 23 donated from the father’s sperm)

Genes Chromosomes are made of a material known as deoxyribonucleic acid (DNA) which contains all of a cells genetic information Each chromosome consists of a single molecule of DNA, which is divided into segments called genes Genes are located in specific places on the chromosome and the provide the necessary instructions for creating proteins Refer to Figure 1.9 on page 17 You are responsible for knowing how the 4 types of molecules; Adenine (A), Guanine (G), Cytosine (C) and Thymine (T) form the building blocks of DNA and how the order in which these building blocks are strung together form the genetic code

Each DNA molecule contains hundreds of thousands of genes Genes determine what kinds of proteins your cells can make and in turn how your body looks and functions Each type of protein a cell creates is designed to do a specific job in your body

Mutations The specific proteins that genes code for depend on the order of the DNA building blocks in the gene A change in the given order of the A,C,T,G building blocks in a segment of DNA is known as a mutation A mutation in a gene can alter the structure and function of the proteins it produces E.g. Individuals with sickle cell anemia have a mutation in the gene that codes for a protein in red blood cells called hemoglobin  this inhibits the ability of red blood cells to carry oxygen to the bodies different organ systems

Mutations Mutations can be random, uncontrolled events or they can be caused by mutagens  substances or factors that can cause a mutation in DNA by physically damaging DNA Some examples of mutagens are electromagnetic radiation (X rays and UV rays from the sun), chemicals such as mercury and tar from cigarettes Not all mutations are harmful  some mutations can occur in portions of DNA that do not code for proteins (mutations in non-genetic parts of a DNA molecule)

Cell Reproduction Cell reproduction is the process by which new cells are formed from existing cells In cell reproduction, there is only one parent cell; the parent cell divides to produce two new cells which are called daughter cells  The two daughter cells are identical to each other and to their parent cell NOTE: Cell reproduction is different than sexual reproduction where two parents mate and the offspring receives half of the genes from each parent (one chromosome from each parent)

Cell Division Cell Division is the process by which a parent cell divides into two daughter cells For single-celled organisms, cell division is the main process by which individuals reproduce and increase a population size For multi-cellular organisms, cell division is the process by which a fertilized egg (a single cell) becomes an adult with millions of cells  It is also the process where lost or damaged cells are replaced

Cell Division A cell cannot simply split down the middle to divide  It has a specialized multi-step division process which includes; Mitosis  The process by which a parent cells nucleus duplicates and divides into 2 equal parts Mitosis is broken down into 4 distinct phases 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase Cytokinesis  Following mitosis, the process by which the two nuclei and the cell contents separate into two daughter cells