BiologyBio- = 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 nucleusexample: all organisms EXCEPT bacteria

Unicellular – an organism made of only one cellexamples: euglena, amoeba, paramecium

Multicellular – an organism made of many cellsexamples: 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 FunctionNucleus – 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 Systems1. 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 LifeMetabolism – 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

C6H12O6+6O2 6CO2+6H2O + energy

Happens in mitochondria

http://www.pbs.org/wgbh/nova/methuselah/phot_flash.html

Click link below

Fermentation – process of releasing stored energy without the use of oxygen.

enzyme

C6H12O6 C2H5OH + 2CO2

yeast cells ferment into ethanol alcohol and carbon dioxide

muscle cells ferment into lactic acid and

energy

C6H12O6 2C3H6O3 + energy

Cell Division and MitosisWhy 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 CycleOrganisms have a life cycle.

Cells also have a life cycle.

Onion Root Tip

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

Metaphase1. Chromosomes line up across equator

Anaphase1. 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 cell Animal 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.

FissionDuring 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

RegenerationRegeneration 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

23

46

Human

Types of Human Cells

Diploid Haploid

# of chromosomes

46 23

Process that produces them

Mitosis Meiosis

Examples Brain cells, skin cells, bone cells

Egg cells and sperm cells

Meiosis Movie

Click to play movie

Meiosis IProphase I

In Prophase I, each duplicated chromosome comes near its similar

duplicated mate

Prophase I is similar to prophase in Mitosis

Meiosis IMetaphase 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 IAnaphase 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 ITelophase I

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

Meiosis IIProphase II

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

Meiosis IIMetaphase II

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

Meiosis IIAnaphase II

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

Meiosis IITelophase 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 ladderDNA

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

1953made a model of DNA

DNA = deoxyribonucleic acid

Nucleotides (3 parts)

1. SUGAR – deoxyribose sugar C5H10O4

2. BASE - Adenine- Guanine- Cytosine- Thymine

3. PHOSPHORIC ACID - H3PO4 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 – TC – 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 Duplication1. Uncoils

2. Hydrogen bond breaks (unzips)

3. New nucleotides replace old (pair up)

RNA = ribonucleic acid

Sugar – ribose sugar C5H10O5

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

DNA RNADeoxyribose sugar Ribose sugar

Thymine Uracil

Double stranded Single stranded

Found in nucleus Found in nucleus and cytoplasm

Click for DNA animation

http://207.207.4.198/pub/flash/24/menu.swf

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

http://207.207.4.198/pub/flash/26/transmenu_s.swf