LECTURE 3 CELL ORGANELLES Sapakhova Zagipa Beisenovna Ph

LECTURE 3. CELL ORGANELLES Sapakhova Zagipa Beisenovna, Ph. D

-nucleus -cytoplasm -nucleolus -cytoskeleton -cell membrane -vacuole -mitochondria -chloroplast -golgi Apparatus -centrioles -lysosomes -ribosomes -endoplasmic reticulum(ER) *Rough ER & Smooth ER 2

Nucleus v. The “brain” of the cell v. Controls all of the cellular activities v. DNA is inside the nucleus 3

Nucleus CHROMOSOMES- are found inside the nucleus carry the information that Chromosomes – determines what traits a living thing will have 4

DNA - Deoxyribonucleic acid 5

DNA - Deoxyribonucleic acid DNA carries the genetic information of a cell Consists of thousands of genes It specifies everything that is needed for the maintenance, function, and replication of the cell It is made up of 4 different bases: (A) adenine (C) cytosine (T) thymine (G) guanine 6

DNA - Deoxyribonucleic acid 7

NUCLEOLUS v. The dark area in the nucleus v. Like a tiny nucleus inside the nucleus. 8

CELL MEMBRANE v holds the cell together v keeps all of the pieces (like the organelles and the cytoplasm) inside the cell v controls what goes in and out of the cell Example: like a big plastic bag with tiny holes in it 9

How does the cell membrane work? v. Has 2 layers of MOLECULES = BILAYER v. Bi means two v. The layers are made up of molecules called phospholipids **THINK OF a sandwich with two pieces of bread and some stuffing on the inside 10

Cell Membrane: PHOSPHOLIPIDS v. Each phospholipids has a HYDROPHOBIC and HYDROPHILIC end • HYDRO = means water • PHOBIC = means afraid • PHILIC = means loving 11

Cell Membrane: PHOSPHOLIPIDS v One end of the molecule is “afraid” of the water and one end “loves” being in the water. v Proteins are stuck inside the membrane v Proteins are across the bilayer and make the holes that let ions and molecules in and out of the cell 12

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Mitochondria v Mito = Mighty / Power v The Power-House of the cell v They break down food molecules so the cell has the energy to live v If a cell needs a lot of energy…it will have more mitochondria 14

The Mitochondria structure has three main parts: OUTER MEMBRANE: covers the mitochondria INNER MEMBRANE: folds many times to increase the surface area because chemical reactions (glycolysis) occur here So…the more space it has the more energy it 15 can create

MATRIX: a fluid that has water and proteins all mixed together (like a solution) • The proteins take the food molecules in and combine them with Oxygen to release the energy 16

Endoplasmic Reticulum v also known as the “ER” v it is an organelle inside the cell that is made up of membranes that are in the CYTOPLASM of the cell v. There are two different üSmooth ER üRough ER 17

Smooth ER v Main function is to collect, maintain & transport things v Shaped slightly tubular v Creates steroids v Stores Ions for the cell to keep nutrients balanced 18

Rough ER v. It has bumps all over it giving it a “rough” appearance v. Bumps are called RIBOSOMES v. ER collects the proteins (built by the ribosomes) and creates a bubble around them v VESICLE- is formed when the ER pinches off a part of its membrane 19

MOVEMENT of VESICLES **The vesicle can then move to the Golgi apparatus or the cell membrane 1) If the vesicle floats to the cell membrane, the proteins are going to be sent out of the cell……or (exocytosis) 2) If they move to the Golgi Apparatus, the proteins will be used inside the cell 20

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EXOCYTOSIS- The release of intracellular molecules (hormones or proteins) 23

Osmosisthe movement of water across the cell membrane 24

GOLGI APPARATUS • Also called the Golgi Complex • It is made up of a stack of flattened out sacs …like a loose stack of pancakes WHAT DOES IT DO? 1) it takes simple molecules and combines them to make larger molecules. 2) takes those larger molecules and puts them into packs called GOLGI VESICLES 25

Think about building a model of a ship (that's the molecule). Then take that model and put it in a bottle (that's the vesicle). 26

Golgi apparatus 27

LYSOSOMES (primarily animal) • They combine with the food taken in by the cell • The enzymes in the lysosome bond to food & digest it (acidic interior) • Next…smaller molecules are released which are absorbed by the mitochondria 28

LYSOSOMES • When an organelle no longer works, the lysosome will attach itself to it and break it down like food (kind of like a cannibal) – Chemicals can then be reabsorbed or excreted • Lysosomes can also destroy the cell if it breaks open accidentally – “Suicide Sacs” – UV light damages lysosome membrane • The enzymes inside the lysosome spread throughout the cell and digest it 29

LYSOSOMES 30

Lysosome Animation 31

CYTOPLASM Protoplasm- everything inside the cell membrane Cytoplasm- everything inside the cell membrane & outside of the nucleus except the cell’s nucleus Cytosol: – Mostly H 2 O – Contains organelles – Contains salts, dissolved gasses & nutrients 32

CYTOPLASM cytoplasm 33

CYTOSKELETON • Chief functions include: – movement of material through the cell for stuff not diffusion or osmosis – maintaining the shape of the cell – keeping the cell from getting smashed 34

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VACUOLE • Vacuoles are “bubbles” that float in the cell • Vacuoles are more important to the survival of plant cells than they are to animal cells 36

VACUOLE: STORAGE IN PLANT CELLS • Vacuoles in plants support structure • Vacuoles hold onto things that the cell might need…like a backpack • There are some vacuoles that hold onto waste products, similar to having a big septic tank • Storing waste products protects the cell from contamination 37

VACUOLE CONT’D So, when there is no water…the vacuole shrinks and the cell wall is the only thing holding the plant together. 38

You will know that a plant's vacuoles are shrinking when you see the plant begin to droop over HOLDING UP THE WALLS 39

Turgor Pressure- force exerted by the water entering (osmosis) the vacuole, which then swells exerting internal force on the cell wall • Causes “rigidity” so the plant my increase by stacking cells 40

Chloroplast 41

Chloroplast • the site of photosynthesis in eukaryotic cells • disk-like structures • composed of a single membrane • surrounding a fluid containing stacks of membranous disks 42

• SOLAR energy radiated from the sun is captured by plants(chloroplast) Chloroplast • Then it is instantaneously changed into ELECTRICAL energy • Then packaged as CHEMICAL energy 43

Chloroplast • photosynthesis takes place inside the chloroplast the process in which plant use Photosynthesis- water, carbon dioxide, and energy form the sun to make food 44

Chloroplast • No energy transformation is 100% efficient • Not all the solar energy captured is converted to electrical and then chemical energy. • Some of it gets lost as heat or other forms of energy (light) 45

Centrioles: • generally appear in animal cells • they look like two cylinders at right angles to one another • when viewed with an electron microscope, the cylinders show up as nine bundles of tiny microtubules arranged in a circle • they help to form the fibers that move chromosomes around when the cell is dividing • as animal cells prepare for cell division these two centrioles separate and go to opposite 46 ends of the cell.

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Ribosomes • small dot-like structures in cells • they are often associated with forming rough ER • Ribosomes are the site of protein synthesis in cells • they are made in the nucleus of the cell • A ribosome can make the average protein in about one minute 48

Ribosome Structure • Ribosomes are made up of proteins and ribonucleic acid(RNA) • These molecules are arranged into two subunits • These subunits are attached to each other and together form the entire ribosome • When viewed through a light microscope the ribosomes appear as dots 49

Types of Ribosomes • There are two kinds of ribosomes 1) Attached to the rough ER 2) floating in the cell cytoplasm • Attached ribosomes make proteins that are used in the ER or transported within the ER • Free ribosomes make proteins that are used in the cytoplasm 50

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Assignment Part A (slides 1 -11) Directions: Write-out and highlight the following questions. Then use your notes to answer them. 1. Which organelle is known as the “Brain” of the cell? 2. If you look at a picture of a cell, how would you recognize the nucleolus? 3. List the 3 main jobs of the cell membrane 4. Explain why the cell membrane has tiny holes made of protein in it. 5. The term hydro means _____. A. If something is hydrophobic it is _____ 52 B. If something is hydrophilic it is _____

Assignment Part B (slides 11 -23) Directions: Write-out and highlight the following questions. Then use your notes to answer them. 1. Which organelle is known as the Power House” of the cell? 2. The mitochondria of a cell share the same job as the _____ (hint- an organ) in the human body. 3. Explain how you could distinguish the rough ER from the smooth ER. 4. What is the main job of the smooth ER? 5. What type of reactions occur on the inner membrane of the mitochondria? (produces energy) 6. The process of H 2 O moving across the cell membrane is called? 53

Assignment Part C (slides 23 -) Directions: Write-out and highlight the following questions. Then use your notes to answer them. 1. What is the main function of a lysosome? 2. What happens if a lysosome breaks open? 3. Explain the difference between cytoplasm and protoplasm. (draw a diagram if it will help you) 4. Why are vacuoles important to PLANTS? 5. Which organelle is the site of photosynthesis? 6. What are three main ingredients for photosynthesis? 54

Assignment Part D (slides 23 -) Directions: Write-out and highlight the following questions. Then use your notes to answer them. 1. Centrioles are usually found in _____ cells. 2. What is the main function of a centriole? 3. List the two places you can find a ribosome in an animal cell. 4. What do ribosomes make? 55

See also wksht to go with questions parts BD 56