Biology Bio- = life -ology = the study of Organisms – living things Cell – smallest unit of an organism that can carry on life functions

Prokaryotic cell – cell with NO nucleus example: bacteria Eukaryotic cell – cell with a nucleus example: all organisms EXCEPT bacteria

Unicellular – an organism made of only one cell examples: euglena, amoeba, paramecium Multicellular – an organism made of many cells examples: animals, trees, mushrooms

Antonie van Leeuwenhoek – made a simple microscope with a glass bead that could magnify up to 270 times

Robert Hooke - discovered the “cell” - looked at a piece of cork - said the cells look like little boxes

CELL THEORY 1.All organisms have one or more cells 2.All cells come from cells (DIVIDE) 3.Cells are basic units of life Matthias Schleiden – all plants are made of cells Theodor Schwann – all animals are made of cells Rudolph Virchow – cells divide to make new cells

Cell Parts and Function Nucleus – control center, directs activities of the cell Cytoplasm – gel-like material inside cell Cell Wall – supports and protects plant cell Cell Membrane – protective layer, allows certain material in and out of cell Chloroplast – green structure in plant cells, allows plants to make their own food

Mitochondria – where energy in food is stored then released; POWERHOUSE Ribosomes – makes proteins Endoplasmic reticulum – folded membrane, moves materials in cell Vacuole –storage for food, water, waste Lysosome – breaks down food, waste, and worn out cell parts Golgi Body – packages proteins

Moving Cellular Material Cell Membrane –allows certain material in and out of cell Selectively permeable – selects what can enter and leave based on size Passive Transport Systems DO NOT use energy to move substances through the cell

3 Types of Passive Transport Systems 1.Diffusion – random movement of molecules from higher concentration to lower concentration until they reach equilibrium (ex. Vanilla in balloon)

2. Osmosis – diffusion of water through a cell membrane (ex. Carrot in salt water) 3. Facilitated Diffusion – transport proteins help large molecules, like glucose, enter the cell (ex. Drive through window of McDonalds)

Active Transport System – energy is needed to move a substance through membrane, like root cells needing minerals from soil (ex. Going back into a stadium after the game)

Endocytosis – cell process that takes in a substance by surrounding it. (ex. How amoeba takes in food) Exocytosis – contents of a vesicle can be released. (ex. Cells in stomach release chemicals to help digest food)

A. Diffusion and Osmosis B. Facilitated Diffusion C. Active Transport D. Endocytosis E. Exocytosis Cell Membrane Transport

Energy for Life Metabolism – Organisms use energy to carry out activities of life, like making food, breaking down food, building cells, moving materials in and out of cells. The total of all chemical reactions in an organism. Enzyme – causes a change and can be used again

Producers – organisms that can make their own food Consumers – organisms that cannot make their own food

Photosynthesis – process of changing light energy into chemical energy (use light to make sugars) START: carbon dioxide, water, light energy END: glucose sugar, oxygen Happens in chlorophyll

Cellular Respiration – process that breaks down food molecules into simpler substances and releases energy (split glucose using oxygen) START: glucose sugar, oxygen END: carbon dioxide, water, energy C 6 H 12 O 6 +6O 2 6CO 2 +6H 2 O + energy Happens in mitochondria

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Fermentation – process of releasing stored energy without the use of oxygen. enzyme C 6 H 12 O 6 C 2 H 5 OH + 2CO 2 yeast cells ferment into ethanol alcohol and carbon dioxide muscle cells ferment into lactic acid and energy C 6 H 12 O 6 2C 3 H 6 O 3 + energy

Cell Division and Mitosis Why do cells divide? Many organisms start as one cell. That cell divides and become two, two becomes four, four becomes eight, and so on. Multi-cellular organisms grow because cell division increases the number of cells. Even after growth stops, cell division is important. Every day, billions of red blood cells wear out and are replaced. During a few seconds, bone marrow can produce six million red blood cells.

Cell Cycle Organisms have a life cycle. Cells also have a life cycle.

Onion Root Tip

Interphase (growth and development) 1. Chromosomes double

Prophase 1. Centrioles divide move toward poles 2. Nuclear membrane disappears 3. Nucleolus disappears 4. Chromosomes appear 5. Spindle fibers appear Mitosis

Metaphase 1. Chromosomes line up across equator

Anaphase 1. Chromosomes move toward poles

Telophase (cytoplasm begins to divide) 1. Chromosomes disappear 2. Spindle fibers disappear 3. Nuclear membrane appears 4. Nucleolus appears

Cytokinesis – cytoplasm divides Plant cells – cell plate (forms new cell wall) Animal cells – furrow (forms new cell membrane) Plant cellAnimal cell

Mitosis Movie Click to play movie

Mitosis in plant cell

Cell division in animal cells and plant cells is similar, but plant cells do not have centrioles and animal cells do not form cell walls. Organisms use cell division to grow, to replace cells, and for asexual reproduction. Asexual reproduction produces organisms with DNA identical to the parent’s DNA. Fission, budding, and regeneration can be used for asexual reproduction.

Fission During fission, an organism whose cells do not contain a nucleus copies its genetic material and then divides into two identical organisms. Example: Bacteria uses fission to reproduce

Regeneration Regeneration is the process that uses cell division to regrow body parts. Examples: sponges, planaria, sea stars

Budding When the bud on the adult becomes large enough, it breaks away to live on its own Examples: hydra

Sexual reproduction results when an egg and sperm join. This event is called fertilization, and the cell that forms is called the zygote. Meiosis occurs in the reproductive organs, producing four haploid sex cells. During meiosis, two divisions of the nucleus occur. Meiosis ensures that offspring produced by fertilization have the same number of chromosomes as their parents. Meiosis and Sexual Reproduction

Sexual reproduction – type of reproduction when two sex cells come together (egg and sperm) Sperm – sex cells formed in the male reproductive organs Egg – sex cells formed in the female reproductive organs Fertiliztion – joining of an egg and sperm Zygote – cell that is formed due to fertilization (diploid) Diploid – when cells have pairs of similar chromosomes Haploid – when cells do NOT have pairs of chromosomes Meiosis – produces haploid sex cells

23 46 Human

Types of Human Cells DiploidHaploid # of chromosomes 4623 Process that produces them MitosisMeiosis ExamplesBrain cells, skin cells, bone cells Egg cells and sperm cells

Meiosis Movie Click to play movie

Meiosis I Prophase I In Prophase I, each duplicated chromosome comes near its similar duplicated mate Prophase I is similar to prophase in Mitosis

Meiosis I Metaphase I The centromere of each chromatid pair becomes attached to one spindle fiber, so the chromatids do not separate in anaphase I. In metaphase I, the pairs of duplicated chromosomes line up in the center of the cell.

Meiosis I Anaphase I In anaphase I, the two pairs of chromatids of each similar pair move away from each other to opposite ends of the cell.

Meiosis I Telophase I In telophase I, the cytoplasm divides, and two new cells form.

Meiosis II Prophase II In prophase II, the duplicated chromosomes and spindle fibers reappear in each new cell.

Meiosis II Metaphase II In metaphase II, the duplicated chromosomes move to the center of the cell.

Meiosis II Anaphase II The centromere divides during anaphase II, and the chromatids separate and move to opposite ends of the cell.

Meiosis II Telophase II As telophase II begins, the spindle fibers disappear, and a nuclear membrane forms around the chromosomes at each end of the cell.

Meiosis Summary

DNA

Double Helix – twisted ladder DNA

Discovering DNA Rosalind Franklin – 1952 discovered that DNA is two chains of molecules in spiral form. X-Ray diffraction of DNA

James Watson and Francis Crick 1953 made a model of DNA

DNA = deoxyribonucleic acid Nucleotides (3 parts) 1.SUGAR – deoxyribose sugar C 5 H 10 O 4 2.BASE - A denine - G uanine - C ytosine - T hymine 3.PHOSPHORIC ACID - H 3 PO 4 P S B

Double helix = twisted ladder shape of DNA Sides of the ladder = phosphoric acid and sugar Rungs of the ladder = nitrogen base pairs A – T C – G Bases are held together by hydrogen bond

When chromosomes are duplicated before mitosis or meiosis, the amount of DNA in the nucleus is doubled. The two sides of DNA unwind and separate.

DNA Duplication 1.Uncoils 2.Hydrogen bond breaks (unzips) 3.New nucleotides replace old (pair up)

RNA = ribonucleic acid Sugar – ribose sugar C 5 H 10 O 5 RNA looks like half of a ladder 4 bases – G,C,A, and U for uracil Different types of RNA tRNA – transfer RNA mRNA – messenger RNA rRNA – ribosomal RNA

How DNA and RNA are different DNARNA Deoxyribose sugarRibose sugar ThymineUracil Double strandedSingle stranded Found in nucleusFound in nucleus and cytoplasm

Click for DNA animation

GENES Most of your characteristics, such as the color of your hair, your height, and even how things taste to you, depend on the kinds of proteins your cells make. DNA in your cells stores the instructions for making these proteins. Proteins build cells and tissues or work as enzymes. The instructions for making a specific protein are found in a gene which is a section of DNA on a chromosome.

GENES Each chromosome contains hundreds of genes. Proteins are made of chains of hundreds or thousands of amino acids. The gene determines the order of amino acids in a protein. Changing the order of the amino acids makes a different protein.

Protein Synthesis (making proteins) Genes are found in the nucleus, but proteins are made on ribosomes in cytoplasm.

1.Transcription – DNA gives information to mRNA (code) mRNA is made from DNA in the nucleus 2. mRNA goes through nuclear membrane to cytoplasm and attaches to ribosome Translation 3. tRNA attach to amino acid 4. tRNA brings amino acid to ribosome and plugs into mRNA * peptide bond holds the two amino acids together 5. When all amino acids are lined up a PROTEIN is formed

Protein Synthesis link s.swf