Cells Study Guide PDF

The nucleus houses and organizes DNA, which contains instructions for making proteins. DNA reads the right genes and copies those genes into mRNA. The mRNA goes through the nuclear pores to the ribosomes which aligns the amino acids in the right order and binds them together. The protein will then...

The nucleus houses and organizes DNA, which contains instructions for making proteins. DNA reads the right genes and copies those genes into mRNA. The mRNA goes through the nuclear pores to the ribosomes which aligns the amino acids in the right order and binds them together. The protein will then go to the rough ER and as the protein comes out, its being folded into the correct shape, chemically modified, and then wrapped into a vesicle of the RER membrane and goes to the golgi It now has a tag on it so it matches specific docking proteins on the motor proteins that carry it on the right microtuble wherever it needs to go. Extra: Mitochondria produces ATP which helps in making the motor walk with the vesicle Lysosome helps unclog cell parts to make protein syntehsis more efficient Cell membrane has receptors to recieve messages on when to read certain genes Microscopes: LM is used in the lab, visible light is passed through the specimen and then through glass lenses. The lenses bend the light in a way that the image is magnified onto film/sensor or onto video screen. Can’t resolve detail finer than 0.2 micrometers. Can magnify 1000x times the actual size of the specimen. Looks more like a blob like u cant see organelles EM focuses a beam of electrons through the specimen or onto its surface. SEM - study surface of a specimen, 3d TEM internal structure of cells, shows transmitted electrons, u can see organelles Eukaryotic vs Prokaryotic Cells Eukaryotic: Bigger, membrane bound nucleus/organelles, linear DNA with histones, membrane receptors, mitosis, cell wall simple when present, cytoskeleton, big ribosomes Prokaryotic: smaller, unbound nucleus/organelles, circular DNA, binary fission, no membrane receptors, complex cell wall, small ribosomes, no cytoskeleton prokaryotic - bacteria, archaea  Eukaryotic - protsts, fungi, animals, plants All cells have cell membrane, cytosol (jelly like) is where the organelles are found, all have chromosomes which carry genes in the form of DNA, all have ribosome Location of DNA differs: in eukaryotic it’s in nucleus, prokaryotic its in nucleoid Prokaryotes interior is the cytoplasm Region between cell membrane and nucleus is the cytoplasm in eukaryotic cells In the cytoplasm, suspended in cytosol, are the organelles Animal cell - most of the cells metabolic activities occur in cytoplasm In animal cells but not plant cells: lysosome, centrosomes/centrioles, flagella In plant cells but not animal cells: chloroplasts, central vacuoale, cell wall, Organelles Nucleus: Protects the DNA from cytosolic enzymes that would destroy it Provides a small space to maximize enzyme/substrate concentrations so that replication and mRNA production is efficient Provides the right environment for those chemical reactions Organizes the DNA to control gene expression through the nuclear matrix (whether it is attached to the nuclear matrix and how tight or loose is it) (i.e. make sure the cell has the right proteins at any given time Nuclear envelope - double membrane enclosing the nucleus, perforated by pores; separates its contents from the cytoplasm Nucleolus - structure involved in production of ribosomes; rRNA is synthesized from instructions in the DNA; proteins imported from the cytoplasm are assembled with rRNA into ribosomal subunits, then subunits exit the nucleus through the nuclear pores to the cytoplasm, where it can be assembled into a ribosome Chromatin - material consisting of DNA and proteins, visible as individual chromosomes in dividing cells Nucleus - houses DNA, riosomes - use info from the DNA to make proteins Nucleus directs protein synthesis by synthesizing mRNA acc to instructions provided by the DNA; mRNA is transported to the cytoplasm via nuclear pores;once it reaches the cytoplasm, ribosomes translate the mRNA’s genetic msg into the primary structure of a polypeptide (transcirbing/translation) DNA is organized into chromosomes (carry genetic info) and the chromosomes are made up of chromatin (protein and DNA) Cilia: Move stuff across cell surfaces like mucus  Moves some single-celled protozoans like paramecia Flagella: Flagellum - locomotion organelle present in animal cells; composed of a luster of microtubles within an extension of the cell membrane Longer and only 1/cell – sperm or up to 6 on bacteria, also found on protozoa For swimming Cilia and flagella are motile appendages containing microtubles. Mitochondria: Breakdown glucose and uses the released energy to make ATP from ADP The inner mitochondrial membrane is in-folded to create more surface area = more e.t.c.’s so more efficient cell respiration Have their own DNA and ribosomes, comes only from the mother Can copy themselves and make their own proteins mitochondria - cellular respiration occurs and ATP is generated Peroxisome: metabolic functions; produces hydrogen perodixde and converts it to water Chloroplasts: For photosynthesis – create sugar from inorganic materials – carbon dioxide and water using the sun’s energy to excite the electrons – the excited electrons are stored in the covalent bonds shared between the C and H atoms They also have their own DNA and ribsomes Collecting the sun’s energy happens in the thylakoid membranes which are stacked and have huge amounts of surface area The chemical reactions to then make the sugar happen in the stroma where the correct enzymes are Chloroplasts - cite of photosynthesis,, converts energy of sunlight to chemical energy stored in sugar molecules, contain enzymes that transfer hydrogen from substrates to oxygen producing hydrogen peroxide. some can use oxygen to break fatty acids into smaller molecules to be transported to mitochondria. Vacuoles: Vacuoles carry out functions performed by lysosomes in animal cells Animal vacuoles can store water, wastes, nutrients – small and fairly numerous Plant vacuoles take up the majority of the cytoplasm of the cell ○ They can actively transport salt to the interior so water will flow in creating turgor pressure ○ Pigments also stored here Protozoans have food vacuoles (from endocytosed food then fuses with lysosome) and Paramecium have contractile vacuoles to squeeze out water to keep the osmostic balance  Plant Vacuoles: storage, breakdown of waste products, hydrolysis of macromolcules, plant growth,pigments that color the cell, hold reserves of important organic molecules, repository of inorganic ions (k, CI), disposal sites for metabolic by products that would endanger the cell if accumulated in the cytosol, protect against predators containing compounds that are poisonous to animals Ribosomes: Protein synthesis - aa are bonded together in a chain based on the sequence of mRNA copied from the DNA Ribosomes - made of RRNA and protein, carry out protein synthesis RER: If proteins are destined for a particular location such as the cell membrane or are to be secreted, a signal sequence directs the ribosome to the RER Protein enters the RER from the ribosome Folds into the correct shape Is modified – may be cut some, carbs added etc. Is transported to the Golgi wraps it in a piece of its own membrane (forming a vesicle to send to the Golgi) Makes phospholipids to replace the membrane it lost Rough ER - has ribosomes, makes secretory proteins, grows in place by adding membrane proteins and phospholipids to its own membrane Golgi: Modifies (add location signals) to the protein so it goes to where it’s supposed to) Molecules that match specific docking proteins on the motor proteins are added to the protein so it “jumps on to the right microtubule Packages (wraps it in a piece of its own membrane) Golgi - active in synthesis, modification, sorting and secretion of cell products, transport vesicles travel here. center of manufacturing, warehousing, sorting, shipping, products are modified and stored to other destinations. Lysosome: Has receptors for binding proteins Fuses with old cell parts, bacteria, or macromolecules in vesicles and breaksthem into components Digest old worn out cell parts to keep the cell unclogged and able to function normally  In macrophages, digest all of the junk that they endocytose like whole bacteria, dried blood, damaged bone, etc. In single cells – they fuse with the endocyotic membrane and become food vacuoles Lysosomes - digestive organelle where macrmolcules are hydrolyzed and recycle intracelular materials SER: Specialized functions in different cells In all cells, can make phospholipids Makes cholersterol - liver Makes steriod hormones testes & ovaries Detoxifies drugs and alcohol - liver Sequesters calcium in muscle cells Smooth ER - no ribosomes, synthesis of lipids, metabolism of carbs, detoxification of drugs/poisons, stores calcium ions Centrioles: Centrosome is a membrane containing 2 centrioles and some proteins Duplicate and move to the cell poles and reforms the cytoskeletal microtubules into spindle fibers to separate the chromosomes Plant cells don’t have them but do have a centrosome May organize the microtubules in normal cytoskeleton Centrosome - area where microtubles are initiated; has a pair of centrioles Cytoskeleton: Made out of many protein fibers (microfilaments) and microtubules The microfilaments are for structure and shape of the cell Microtubules act as train tracks for motor proteins to transport stuff through the cell Determines the cell’s shape and therefore what DNA is read – must be attached to nuclear matrix and is attached to the cell membrane and ECM Cytoskeleton: reinforces cells shape, , mechanical support to the cell and maintains shape functions in cell movement, made of protein includes: microfilaments- built from actin (gobular protein) Microfilaments are thin rods, functioning in muscle contraction, amoeboid movement microtubles - guide secreory vesicles from the golgi to cell membrane, separate chromosomes during cell division, Microtubles shape the cell, guide organelle movement, separate chromosomes in dividing cells.  microvilli - projections that increase the cells surface area Nucleolos: Clump or RNA and proteins that will become the ribosomes Cell wall: Plants – cellulose – helps create turgor presssure, provides structure Bacteria - chitin Cell wall 0 maintains cells shape and protects from mechanical damage, made of cellulose, polysaccharides, and protein Specialized Cells: muscle cells - contract skin cells - make you water-proof and block out pathogens plant cells - do photosynthesis nerve cells (brain) - communicate with other cells glandular cells - send hormones (messages) to other cells sperm cells - swim and fertilize eggs white blood cells - locate and destroy pathogens red blood cells - carry oxygen What cells do: Divide and make new cells Do Cellular Respiration (convert energy) Do chemical reactions with enzymes Send and receive messages Bring in/Send out big and small things What cells move? Embryonic, cancer, single, during cell division, healing, nerve cells (reach out  filopodia – if a connection is used its strengthened – if not – its destroyed), macrophages, protozoans Types of Movement: amoeboid, cilia, flagella, muscle contraction, intracellular transport Tissues Plants - plasmodesmata animals - tight junctions ( prevent leakage of fluid), desmosomes (attach muscles cells to each other), gap junctions ( provide channels from one cell to an adjacent cell, consist of membrane prtoiens that surround a pore htorugh which ions and small molecules may pass, for communication between cells in tissues) Cell junctions: Tight Junctions – between epithelial cells – proteins that hook the cells together tightly so that there is no leakage between the cells Desmosome – tight junction with extra reinforcing proteins tying the cytoskeletons of neighboring cells together – keeps cells from ripping apart Gap Junctions – found in smooth muscle – tiny protein tunnels that ions can pass through from cell to cell Animal Tissue: Epithelium Square or rectangular, hooked together by tight junctions Form Leakproof Linings and barriers Selectively secrete and absorb Animal Tissue: Nervous Big cell bodies with many short extensions to receive information and one long  axon to send information Fast signal transmission since almost touch the cells they are communicating with with their extensions Animal Tissue: Skeletal muscle Long tube-shaped cells packed with contractile proteins and many nuclei ECM between cells – each muscle is connected to an axon for quick communication Animal Tissue: Smooth muscle Spindle-shaped cells surrounding hollow organs to squeeze the contents to move them Have gap junctions so contract all together Animal Tissue: Connective Tissue Bone Cells not joined – separated by ECM Amt. and type of matrix gives the tissue it’s characteristics Matrix is always a mix of fibrous proteins and liquid) Bone is strong and supports weight because: Bone is mostly matrix; Matrix is hardened with calcium Animal Tissue: Connective Tissue Adipose Stores fat away from enzymes but also used for cushioning and insulation Little matrix – more about the cells Animal Tissue: Connective Tissue Dense Fibrous Makes up tendons, ligaments, underneath of skin – has to be really strong Almost entirely matrix – fibrous proteins with very little liquid 1c 2b 3d 4d 5b 6c 7e 8a