1. golgi apparatus
1.1. Stacks of flattened sacks called cisternae
1.1.1. Sacks are constantly budding off and reforming
1.2. collects and processes molecules
1.3. after processing molecules can be transported in the golgi vesicles to other parts of the cell or outside the cell.
1.3.1. realeasing the molecules from the cell is called secreation and the pathway is called the secretory pathway
1.4. functions
1.4.1. golgi vesicles are used to make lysosomes
1.4.2. Sugars are added to proteins to make molecules known as glycoproteins
1.4.3. Sugars are added to lipids to make glycoproteins. Glycoproteins and glycolipids are important components of membranes and are important molecules in cell signaling
1.4.4. During plant cell division, golgi enzymes are involved in the synthesis of new cell walls
1.4.5. In the gut and the classic exchange system common cells called goblet cells release a substance called mucin from the golgi apparatus. Mucin is one of the main components of mucus
2. lysosomes
2.1. simple sacs surrounded by a single membrane (0.1 -0.5 um in diamiter)
2.2. in plant cells the vacuole can act as a lysosome although ones seen in animal cells are also present
2.3. lysosmes contain digestive ensymes calles hydrolase becasue they carry out hydrolisis
2.3.1. these enzymes must be kept seperate from the rest of the cell to prevent damage
2.4. lysosomes are responsible for breaking down unwanted substances and structues
2.4.1. old organelles
2.4.2. whole cells
2.5. lysosomes have a pH of 4-5
2.6. enzymes (contain 60+)
2.6.1. examples
2.6.1.1. lipases
2.6.1.1.1. for breaking down lipids
2.6.1.2. nucleases
2.6.1.2.1. for breaking down nucleic acids
2.6.1.3. proteases
2.6.1.3.1. for breaking down proteins
2.6.2. synthesied at the RER and dilivered by the golgi apparatus
2.7. activities
2.7.1. getting rid of unwanted cell components
2.7.1.1. lysosomes engluf and destroy unwanted cell components inside the cell
2.7.1.1.1. molecules and organelles
2.7.2. endocytosis
2.7.2.1. lysosomes may fuse with the endocytic vacuoles formed and realease their enzymes to digest their contents
2.7.3. exocytosis
2.7.3.1. lysosmal enzymes may be realeased from the cell for extracellular digestion
2.7.3.1.1. replacement of cartilage bone during development
2.7.3.1.2. the heads of sperms contain a special lysosme the acrsome for digesting the path through the layers of the egg just before fertalisation
2.7.4. self- digestion
2.7.4.1. contents of lysosme realeased into the cytoplasm, the whole cell is digested (autolyisis)
2.7.4.1.1. tadpole tail is reabsorebed during metamorphisis
2.7.4.1.2. uterus is restored to its normal size after pregnacy
2.7.4.1.3. after death of an individual as the membranes lose their partial permeability
3. mitochondira
3.1. Structure
3.1.1. 1 um in diameter
3.1.2. many different shapes but normally sausage shaped
3.1.3. surrounded by two membranes
3.1.3.1. the inner membrane is folded in finger like cristae wich project into the interior of the mitochondiron which is called matrix
3.1.3.2. the space between the two membranes is called intermembrane space
3.1.4. responsible for aerobic respiration
3.1.4.1. a cell that requires more energy contains more mitocondira
3.2. Functions of mitochondria
3.2.1. aerobic respiration
3.2.1.1. reactions take place in which energy is released from energy rich molecules such as sugars and fats. most of this energy is transfered to ATP
3.2.1.2. the reactions for respiration takes place in solution in the matrix and in the inner membrane
3.2.1.2.1. the maitrix contains enxymes in solutions.
3.2.2. synthesis of lipids
3.3. role of ATP
3.3.1. this is the energy carrying molecule found in all living cells. it is known for being the universal energy carrier
3.3.2. leaves mitocondira after being made to go to the rest of the cell where energy is needed
3.3.2.1. energy is realeased by it being broken down (hydrolisis reaction) into ADP. ADP can then go back to the mitochondria and be converted back to ATP during respiration
4. microtubeules
4.1. long ridgid tubes found in the cytoplasm
4.2. 25nm in diamiter
4.3. together with actin filaments and intermediate filaments they make up the cytoskeleton of the cell (cell shape)
4.4. made up of a protein called tubulin
4.4.1. a-tublin and ß-tublin
4.4.1.1. combine to form dimers (double molecules). these dimers then join end to end to form long 'protofiliments' (polymerisation). 13 protofilemts line up alongside eachother in a ring to form a cylinder with a hollow center
4.5. functions
4.5.1. Secretary vesicles and other organelles and so components can be moved along the outside surfaces of the microtubules, forming an intracellular transport system, as in the movement of golgi vesicles during exocytosis
4.5.2. During nuclear division, a spindle made from microtubules is used for the separation of chromatids or chromosomes
4.5.3. Microtubules form part of the structure of centrioles
4.5.4. Microtubules form an essential part of the mechanism involved in the beating movements of cilia and flagella
4.6. the assembly of microtubles from tublin molecules is controled but microtuble organization centers (MTOCs), because they are very simple they can be brocken down and formed very easily by the MTOCs
5. centrosomes
5.1. the main mictoruble organising cernter in anmial cells
5.2. make the spindle for nuclear division
6. cillia and falgella
6.1. whip-like structures projecting from the surface of many animal cells and the cells of many unicellular organisms; they beat, causing locomotion or the movement of fluid across the cell surface
6.2. structure
6.2.1. composed of 600 different polypetides
6.2.2. contain 2 centeral microtubles and a ring of nine microtuble doplets (MTDs)
6.2.2.1. A microtuble
6.2.2.1.1. complete ring of 13 profilements
6.2.2.1.2. has inner and outer arms
6.2.2.2. B microtuble
6.2.2.2.1. attached to a incomplete ring with only 10 proflilentets
6.2.2.3. the outside of these us calles axoneme
6.2.3. basal body is a structure found at the base
6.3. beating mechnaism
6.3.1. caused by the protein dynein arms making contact with neighbouring microtubles. the sliding motion is converted into bending by other parts of the cilium
6.4. functions
6.4.1. single-celled organisms in fluid use the cilia and flagella for locomotion
6.4.2. in vertebrates cillia is found on some epithelial cells
6.4.2.1. they maintain a flow of mucous which removes debries such as dust and bacteria from the respiratory tract
6.5. falgella
6.5.1. whip-like structures projecting from the surface of some animal cells and the cells of many unicellular organisms; they beat causing locomotion or the movement of fluid across the cell surface; they are identical to the structure of cillia but longer
7. cell wall
7.1. structure
7.1.1. relativley ridgid
7.1.2. the primary wall consists of parallel fibers of the polysaccharide cellulose running through the matrix of other polysaccarides such as pectins and hemicelluloses
7.1.3. cellulose
7.1.3.1. inelastic
7.1.3.2. high tensile stength
7.1.3.2.1. in most cells extra layers of cellulose are added to the first layer of the primary wall, forming the secondary wall
7.2. functions
7.2.1. Mechanical strength and support for individual cells and the plant. Lignification is one means of support. Turgid tissues are another means of support that is dependent on the strong cell walls
7.2.2. Cell walls prevent cells from bursting by osmosis if cells are surrounded by a solution with a higher water potential
7.2.3. Different orientations of the layers of cellulose fibers help determine the shape of the cells they grow
7.2.4. The system of interconnected cell walls in a plant is called the apoplast. It's a major transport route for water, inorganic ions, and other materials
7.2.5. Living connections through neighboring cell walls, the plasmodesmata, help form another transport pathway through the plant known as the symplast
7.2.6. The cell walls of the root endodermis are impregnated with suberin, a waterproof substance that forms a barrier to the movement of water, thus helping in the control of water and mineral ion uptake by the plant
7.2.7. Epidermal cells often have a waterproof layer of waxy cutin, the cuticle, on their outer walls. This helps reduce water loss by evaporation
8. microvilli
8.1. Greatly increases the surface area of the cell surface membrane
8.2. Finger like extensions of the cell surface membrane
9. nucleaus
9.1. nuclelus
9.1.1. The different parts of the nucleolus only come together during the manufacture of ribosomes and separate when ribosome synthesis seizes (nucleolus disappears)
9.1.2. Around the core it is less dense where ribosomal subunits are assembled, combining the RNA with ribosomal proteins imported from the cytoplasm
9.1.3. containing genes for making tRNA
9.1.4. Making ribosomes using the information from DNA
9.1.5. one or more might be present (one is the most common)
9.1.6. contains a core of DNA from chromosomes which contain genes that code for RNA
9.2. chromosomes and chromatin
9.2.1. Nucleus controls activities of the cell because of the genes
9.2.2. contain DNA which are organized into functional groups called genes
9.3. nuclear envelope
9.3.1. Has small pores called nuclear pores to allow exchange between the nucleus and the cytoplasm
9.3.1.1. entering (to help make ribosomes)
9.3.1.1.1. hormones
9.3.1.1.2. ATP
9.3.1.1.3. nucleotides
9.3.1.2. leaving (for protein sythesis)
9.3.1.2.1. mRNA
9.3.1.2.2. tRNA
9.3.1.2.3. ribosomes
9.3.2. Formed by the two membranes surrounding the nucleus
10. cell surface membrane
10.1. 7nm thick
10.2. Partially permeable to control the exchange between the cell and its environment
11. endoplasmatic reticulum
11.1. types
11.1.1. smooth
11.1.1.1. In the liver SER is involved in drug metabolism
11.1.1.2. storage site for calcium ions (explains abundance in muscle cells where calcium ions are needed for contraction)
11.1.1.3. synthesis of lipids and steroids such as cholesterol and reproductive hormones (oestrogen and testosterone
11.1.2. rough
11.1.2.1. used for protein synthesis
11.1.2.2. Called rough because of the ribosomes attached to the outside
11.2. Continuous with the outside of the nuclear envelope
11.3. processes take place separate from the cytoplasm
11.4. membranes from flattened components called sacs or cisternae
12. ribosomes
12.1. subunits
12.1.1. quoted as S
12.1.2. large and small
12.1.3. Measurement of how fast substances sediment in a high speed centrifuge (faster sedimentation higher S number)
12.1.3.1. prokaryotes ribosomes are 70S
12.1.3.2. eukaryotes ribosomes are 80S
12.2. Allow all interacting molecules (mRNA, tRNA, amino acids, regulatory porteins) involved in protein synthesis together in one place
12.3. not visible under light microscope
12.4. made out of rRNA and proteins
13. centrioles
13.1. one of two small, cylidrical structures, made from microtubles, found just outside the mucleous of an animal cell, in a region known as the centrosome; they are also found at the bases of cillia and flagella reqired for their movements
13.2. not visible under a light microscope
13.3. 500nm long
13.4. formed by a ring of short microtubles. each centiole contains nine triplets of microtubles
13.5. needed for production of cillia
14. chloroplasts
14.1. elongated shape
14.2. 3-10 um in diameter
14.3. surrounded by two membranes forming the chloroplast envelop
14.3.1. the membrane system consists of fluid-filled sacs called thylakoids
14.4. carries out photosynthesis
14.4.1. light energy is absorbed by photosynthetic pigments, particularly chlorophyll
14.4.1.1. in places the thylacoids form flat disc-like structures that stack up like piles of coins forming structures called grana
14.4.2. uses the energy and reducing the power generated during the forst stage to convert carbon dioxide into sugars. this takes place in the storma. the sugars made may be stored in the form of starch garins.
14.4.2.1. lipid droplets are also seen in the storma. they are reserves of lipid for making membranes or are formed for the breakdown of internal membranes as the chloroplast ages.
14.5. contain their own genetic material
15. vacuoles
15.1. support
15.1.1. the solution is relativley concentrated. water therefore enters the vacoules by osmosis, inflating the vacuole and causing a build up of pressure. A filly inflated cell is described as trugid. turgid tissue help to support the stems of plants that lack wood
15.2. lysosomal activity
15.2.1. plant vacuoles contain hydorlase and act as lysosomes
15.3. secondary metabolites
15.3.1. Plants contain a wide range of chemicals known as secondary metabolites which, although not essential for growth and development, contribute to survival in various ways. These are often stored in vacuoles..
15.3.1.1. Anthocyanins are pigments that are responsible for most of the red, purple, pink and blue colors of flowers and fruits. They attract pollinators and seed dispersers
15.3.1.2. Certain alkaloids and tannins deter herbivores from eating the plant
15.3.1.3. latex, a Milky fluid, can accumulate and vacuous, for example in rubber trees. The latex for the opium poppy contains alkaloids such as morphine from which opium and heroin are obtained
15.4. food reserves
15.4.1. Food reserves, such as gross in sugar beet, or mineral salts, may be stored in the vacuole. Protein storing vacuoles are common in seeds
15.5. waste products
15.5.1. Waste products, such as crystals of calcium oxalate, may be stored in vacuoles
15.6. growth in size
15.6.1. Osmotic uptake of water into the vacuole is responsible for most of the increase in volume of plant cells during growth. The vacuole occupies up to 1/3 of the total cell volume