Learning about the building blocks of life Unit 5 - Cells Learning about the building blocks of life

What are cells? Definition: - the basic unit of life that performs life functions for the organism Every living thing is made of cells!!! Unicellular (one cell) Ex. bacterium Multicellular (many cells) Ex. dog Robert Hooke

Cell Theory All living things are made of cells. Cells are the basic unit of structure and function. Cells come from other cells.

Cell parts Cells have small tiny structures inside that have specific jobs (like mini organs) called organelles and float in the cell, much like fruit in Jello

Basic Animal Cell Model (cytoplasm)

Basic Plant Cell Model

Cell organelles 1. Cell membrane Have receptor molecules (allow cells to communicate with one another) Controls what goes in/out of cell; exchanges materials Keeps shape of cell

Cell Organelles Cell Membrane Continued: Receptor Molecules: Bind to messengers (hormones, molecules) from other cells Allow cells to ‘communicate’ with one another to maintain homeostasis (internal stability) Chemical Messengers

Cell Parts 2. Cell Wall (plants) 3. Nucleus (has a nucleolus) Made of cellulose; gives cell shape and protection Plants have both a cell wall and cell membrane Control center of the cell; holds chromosomes (DNA is the protein recipe)

Cell Parts 4. Chromosome 5. Cytoplasm Contains coiled DNA (genetic info) found in nucleus; code to make proteins Jellylike material inside cell that holds organelles in place; like Jello

Cell Parts 6. Mitochondria ‘Little engines of the cell’; cellular respiration (energy production) happens here; powerhouse Glucose (sugar) made into energy (ATP) Sperm Cell: Tons of mitochondria to help sperm with long trip to the egg cell

Cell Parts 7. Endoplasmic Reticulum 8. Ribosomes Transport system of cell; moves protein; like a highway Rough has ribosomes attached, smooth has none Make (synthesize) proteins from amino acids; gets the recipe (code) from DNA in nucleus

Cell Parts 9. Vacuole 10. Chloroplast (plants) Storage of waste, food, water Small in animals and large in plants Site of photosynthesis; contains chlorophyll (green pigment)

Cell Parts Chloroplast continued: Photosynthesis Reaction: Needed Produced Carbon Dioxide + Water Glucose + Oxygen + Water *Then, the glucose can be used for cellular respiration in both plant and animal cells Sunlight

Cell Parts 11. Golgi apparatus 12. Lysosome (Animal Cells) Packages proteins for transport (like UPS) Looks like stack of pancakes Breakdown and recycling center (has enzymes)

Label the Animal Cell

Cell Type Examples Stained Cheek Cells Red Blood Cells Nerve Cells

How do molecules get into and out of a cell Active vs. Passive Transport: Active Requires energy (ATP) to move molecules Often from low to high concentration (walking uphill) or molecules are large Passive Does not require energy Moves molecules from high to low concentration (going downhill)

How do things pass in/out of the cell? Remember, the cell membrane controls what comes in and out of cell (even bad stuff can get in!) Examples of Passive Transport: Diffusion - molecules moving from high concentration to low concentration ex. Perfume spray, balloon demo Osmosis - water moving from high concentration to low concentration across a membrane ex. Cup O’ Noodle Soup

How do cells make more of themselves? To make more body type cells, use: mitosis – making an exact copy of body type cells such as skin, blood cells, etc. to grow and repair. To make more sex type cells, use: meiosis - producing sex cells for reproductive purposes; eggs and sperm (have ½ the number of chromosomes)

Mitosis in Humans First, parent cell info is all copied so 46 chromosomes now become 92 chromosomes Parent cell then divides evenly in two, to create 2 cells with 46 chromosomes each Parent cell (46 chromosomes) Parent cell (92 chromosomes) Daughter cells (46 chromosomes each)

Mitosis in Humans Interphase – Cell is not dividing (growing, doing cell activities) DNA will replicate (double)

Phases of Mitosis 1. Prophase DNA condenses into organized chromosomes Nucleus disappears

Phases of Mitosis 2. Metaphase Replicated chromosomes line up down Middle of cell

Phases of Mitosis 3. Anaphase Replicated chromosomes split away-move apart to opposite sides of cell

Phases of Mitosis 4. Telophase and Cytokinesis Nucleus comes back Chromosomes uncoil Cytoplasm splits = 2 new identical cells

END RESULT OF MITOSIS!! Don’t Forget: Mitosis results in 2 new IDENTICAL body-type cells!!!! 46 46 46

Name that Phase 2. 1. Anaphase telophase 3. 4. Prophase metaphase

Meiosis in Humans The cells responsible for making sex cells (sperm/egg) first replicate their DNA. (46  92) The replicated DNA is then divided into two cells. (46 chromosomes in each cell) The two cells further divide to create a total of four cells by the end. Cells at the end have only 23 chromosomes; not the normal 46. Parent cell (46 chromo) Parent cell (92 chromo) New cells (46 chromo each) Daughter cells (23 chromo each)

Mitosis vs. Meiosis in Humans Parent cell has 46 chromosomes (23 prs) Daughter cell has 46 chromosomes Get 2 identical cells at end Cells are “diploid”; chromosomes occur in pairs Meiosis Parent cell has 46 chromosomes (23 prs) Daughter cell has 23 chromosomes (NO PAIRS) Get 4 cells at the end (sperm or egg) Cells are “monoploid”; cells have half the # of chromosomes

What do you think happens when cells can’t stop dividing? Most of the time, cells are not dividing, instead they are just performing cell activities. When a cell abnormally divides – it doesn’t get the message to stop – this results in cancer. Cancer is uncontrolled cell division

Cell Organization Cells Tissue Organs Organ Systems Organism