Unit 2 Notes Cellular Transportation And The Cell Cycle

Cell Transportation: 2 main types 1. Passive transport: Does not require energy from the cell Moves downhill, with the concentration gradient

Cellular Transportation Type 2 2. Active Transport: Requires energy to occur. 2. Active Transport: Requires energy to occur. Moves uphill, against the concentration gradient.

Passive Transport (No energy required) 3-Types

1 st Type Passive Transport Simple Diffusion : Movement of any substance from areas of higher to lower concentrations Simple Diffusion : Movement of any substance from areas of higher to lower concentrations diffusion animation diffusion animation diffusion animation diffusion animation

2 nd Type Passive Transport Osmosis: Movement of water from areas of higher to lower concentrations Osmosis: Movement of water from areas of higher to lower concentrations

3 rd Type Passive Transport Facilitated diffusion: Movement of substances from higher to lower concentration with help from a protein molecule Facilitated diffusion: Movement of substances from higher to lower concentration with help from a protein molecule Animation: How Facilitated Diffusion Works Animation: How Facilitated Diffusion Works

2-Types of Active Transport (Energy Required) 1. Exocytosis: The expulsion of particles from the cell. 2. Endocytosis: surrounding and engulfing particles. Pinocytosis: Cell drinking – the cell takes in liquids. Pinocytosis: Cell drinking – the cell takes in liquids. Phagocytosis: Surrounding and taking in of large particles. Phagocytosis: Surrounding and taking in of large particles.

Phagocytosis Animation: Phagocytosis Animation: Phagocytosis Animation: Phagocytosis Animation: Phagocytosis

Solute vs Solvent Solute: The dissolved substance in a liquid. Solvent: The liquid that the solute is dissolved in: Usually water

Types of solutions Isotonic solution Concentrations of solute are equal in the cell and the solution. (cell=solution) Concentrations of solute are equal in the cell and the solution. (cell=solution) Water moves back and forth at the same rate. Water moves back and forth at the same rate. Water in =Water Out Water in =Water Out

Hyp-O-tonic solution (Hyp-Ohh no I’m swelling-tonic) Hyp O tonic: Concentrations of solute are higher in the cell than in the solution (cell- higher, solution-lower) Hyp O tonic: Concentrations of solute are higher in the cell than in the solution (cell- higher, solution-lower) Water moves into the cell. Water moves into the cell. The cell swells and can burst. The cell swells and can burst.

Hypertonic Solution Concentrations of solute are lower in the cell than in the solution (cell-lower, solution-higher) W Water moves out of the cell. The cell shrinks.

Limits to cell size A cells size is limited, so organisms grow by cellular division. A cells size is limited, so organisms grow by cellular division. The cells of a baby are the same size as the cells of an adult. The cells of a baby are the same size as the cells of an adult.

So… Why Can’t cells just grow larger???

Three factors that limit the growth of cells 1. Diffusion across cell surface. 1. Diffusion across cell surface. 2. Shortage of DNA. 2. Shortage of DNA. 3. Surface to volume ratio. 3. Surface to volume ratio.

Diffusion Diffusion is efficient over short distances, but becomes inefficient and slow over large distances. Diffusion is efficient over short distances, but becomes inefficient and slow over large distances. So…cells that are large have a more difficult time getting nutrients into the cell and waste products out of the cell. So…cells that are large have a more difficult time getting nutrients into the cell and waste products out of the cell.

DNA A cell cannot survive without sufficient amounts of DNA to make necessary proteins Unusually large cells must have multiple nuclei in order to supply needed DNA

Surface Area to Volume Ratio As a cell’s size increases, its volume increases faster than its surface area As a cell’s size increases, its volume increases faster than its surface area

Cell Reproduction Mitosis: Asexual reproduction (Cell Cycle) Mitosis: Asexual reproduction (Cell Cycle) The process by which one cell divides into two cells, both identical to the original parent cell The process by which one cell divides into two cells, both identical to the original parent cell

The Dreaded “C” Words! Chromatin Chromatin Chromosomes Chromosomes Chromatid Chromatid Centromeres Centromeres Centrioles Centrioles

Chromatin Relaxed DNA.

Chromosomes Condensed DNA. Condensed DNA. DNA that is preparing to undergo cellular division DNA that is preparing to undergo cellular division Can now be seen with a microscope. Can now be seen with a microscope.

Chromatids and Centromeres Sister Chromatids: Halves of a duplicated parent chromosome. Sister Chromatids: Halves of a duplicated parent chromosome. Centromeres: The structure that joints two sister chromatids. Centromeres: The structure that joints two sister chromatids.

Chromatin and Chromosome

Centrioles- Produce the spindle and aid in replication

The Cell Cycle The process of asexual reproduction (mitosis) of the cell The process of asexual reproduction (mitosis) of the cell Contains three major parts Contains three major parts 1. Interphase 2. Mitosis 3. Cytokinesis 1. Interphase 2. Mitosis 3. Cytokinesis

The Cell Cycle

Part One of the Cell Cycle Interphase The cell spends the majority of its life in interphase. The cell spends the majority of its life in interphase. A time in which the cell is preparing for division. A time in which the cell is preparing for division.

Interphase 3-Parts G-1: Maturation. G-1: Maturation. S-Phase: DNA replicates - makes a duplicate copy of itself. S-Phase: DNA replicates - makes a duplicate copy of itself. G-2: Organelles replicate and final preparations for division. G-2: Organelles replicate and final preparations for division.

Mitosis Mitosis Division of the nucleus 4-phases Prophase Metaphase Anaphase Telophase PMAT

Parts of Mitosis Prophase The chromatin condense to form visible chromosomes The chromatin condense to form visible chromosomes The nuclear envelope begins to dissolve The nuclear envelope begins to dissolve The centrioles divide and begin to migrate to opposite sides of the cell The centrioles divide and begin to migrate to opposite sides of the cell

Parts of Mitosis Cont… Metaphase Centrioles have moved to opposite sides of the cell Centrioles have moved to opposite sides of the cell The spindle has formed The spindle has formed Chromosomes are lined up in the middle of the cell across the equator Chromosomes are lined up in the middle of the cell across the equator

Parts of Mitosis Cont… Anaphase The centromeres split and the spindles pull the sister chromatids apart toward opposite sides of the cell The centromeres split and the spindles pull the sister chromatids apart toward opposite sides of the cell

Parts of Mitosis Cont… Telophase The chromosomes move to opposite sides of the cell. The nuclear envelope begins to reform around each set of chromosomes at opposite sides of the cell.

Cytokinesis Division of the cytoplasm Begins to occur during telophase Different in plants and animal cells

Cytokinesis Cont… Animal cells: the plasma membrane pinches in to form two separate cells Animal cells: the plasma membrane pinches in to form two separate cells Plant cells: A rigid cell plate begins to form between the two new cells, dividing them and becoming a cell wall. Plant cells: A rigid cell plate begins to form between the two new cells, dividing them and becoming a cell wall.

mitosis animation mitosis animation

Control of the Cell Cycle The cell cycle is controlled by proteins and enzymes The cell cycle is controlled by proteins and enzymes Contact with other cells causes cell to stop dividing. Contact with other cells causes cell to stop dividing. Cell stop dividing when they lose contact with other cells Cell stop dividing when they lose contact with other cells

Cancer Uncontrolled cell growth resulting in tumors Metastasis: Cells break lose and travel through the circulatory system spreading throughout the body.

Causes of Cancer Environmental factors that damage genes. Environmental factors that damage genes. Ex: Cigarette smoke, UV rays from the sun, air and water pollution, viruses Ex: Cigarette smoke, UV rays from the sun, air and water pollution, viruses