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112 Cards in this Set
- Front
- Back
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What are the cell theories?
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1. Cells are the basic functional unit of life.
2. All cells are made from existing cells. 3. All living organisms are made of cells or products of cells. |
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What is the function of a nucleus?
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Contains DNA, instructions for cellular life
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What is the function of a mitochondria?
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Location of cellular respiration, providing energy for cells
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What is the function of a chloroplast?
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Location of photosynthesis, converting light energy into chemical energy in autotrophs, not animal cells.
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What is the function of the rough endoplasmic reticulum?
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Responsible for protein synthesis and transportation around the cell.
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What is the function of the golgi body?
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Responsible for packaging and transporting molecules out of the cell.
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What is the function of a lysosome?
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Contains digestive enzymes used to breakdown material or used for programmed cell death (apoptosis)
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What is the function of the vacuole?
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Provide a storage area in cells. It is also used to provide structure to plant cells and are large and permanent. In animal cells however they are smaller and temporary.
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When are cells multicellular?
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When theyhave specialised cells to carry out particular functions, eg: nerve cells or red blood cells.
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What is a tissue?
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Specialised cells orginized into a group to perform a specific function, eg: nerve cells or red blood cells.
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What is an organ?
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Specialised tissue organised into a group to perform a specific function.
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What is an organ system?
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A group of organs organised into a group to perform a specific function.
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Describe a light microscope and its advantages and disadvantages?
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It uses light to illuminate the object and lenses to focus the light and magnify the image. Positives: they produce a colour image and the specimen can be alive whilst under observation.
Negatives: the magnification and resolution are both low |
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Describe a electron microscope and its advantages and disadvantages?
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It uses electrons to illuminate the image and magnets to focus the electrons.
Positives: magnification and resolution are both very high Negatives: large machines, produce black and white images and can only observe specimens if they're dead or non-living. |
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Why is cell size limited?
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Surface Area: the larger the surface area availible for diffusion, the more diffusion can occur, increasing efficiency but not the rate of diffusion.
Volume: the smaller the volume the more efficient diffusion is as there is less distance for materials to move. - This is known as surface area to volume ratio. The larger the surface area to volume ration the more efficient diffusion is. |
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Why do cells need a cell membrane?
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A cell needs a cell membrane in order to provide both structure and to maintain an internal environment different to that of the external environment.
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What is the purpose of a cell wall?
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To provide plant and bacterial cells with structure to help maintain the cells shape.
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What is the fluid mosaic model and what does it mean?
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It is the internal structure of the plasma membrane.
Mosiac- made of many small parts Fluid- flexible |
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What is a cell membrane made up of?
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Fluid inside and outside the cell, its contains a phospholipid bilayer containing a hydrophilic phosphate head and hydrophobic tails to form a bilayer. The membrane also includes glycoprotein, a protein with a branched carbohydrate chain used in cell recognition.
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What determines movement across membranes?
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Energy- in the case of active and bulk transport
Difference in concentraion of a substance- in the case of diffusion Difference in the concentration of a substance unable to cross a partially permeable membrane- in the case of osmosis. |
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What is diffision?
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It is the netmovement of a substance from an area of high concentration to an area of low concentration, down a concentraion gradient, eg: oxygen diffusing into the blood.
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What is osmosis?
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Osmosis is the net movement of water across a partially permeable membrane from an area of high concentration to an area of low concentraion. This often occurs to balance the concentration between two solutions when another molecule is unable to cross the membrane.
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What is hypertonic?
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When the concentration of solute is higher than that of the comparison, water will move out of the cell.
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What is hypotonic?
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When the concentration of solute is lower than that of the comparison, water will move into the cell.
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What is isotonic?
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When the concentration of solute is the same to that of the comparison, there will be no net movement of water.
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What is active transport?
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Active transport is the movement of a substance against the concentration gradient from high to low. It is an energy requiring process. This occurs through the protein pumps in the phospholipid bilayer.
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What is bulk transport?
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Bulk transport is the transport of large particles into or out of the cell involving the folding of the cell membrane.
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What is exocytosis?
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Excytosis is the movement of large particles out of the cell and the utilisation of the secretory vesicles.
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What is endocytosis?
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Endocytosis is the movement of large particles into the cell and untilises endosomes.
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What is pinocytosis?
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Pinocytosis is the ingestion of liquid particles.
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What is phagocytosis?
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Phagocytosis is theingestion of solid particles.
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What is a bio-macromolecule?
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It is a large organic molecule found in living organisms.
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What is the definition of organic?
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Organic molecules contain carbon, hydrogen and oxygen and are usually produced by living organisms, eg: polsaccharides, lipids, nucleic acids and proteins.
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What is the definition of inorganic?
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Inorganic molecules do not contain carbon, hydrogen and oxygen, although they may contain two of these three, eg: CO2, CH4 and H2O.
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Is water organic or inorganic?
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Inorganic
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What are some properties of water?
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- It is adhersive and cohesive
- Is less dense as a solid than as a liquid - Releases a large amount of heat when it evaporates - Absorbs a large amount of heat without changing tempreture - dissolves most solutes, practically all chemical processes of biological significance occur in a watery medium. |
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What are polysaccharides?
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Polysaccharides are molecules composed of carbon, hydrogen and oxygen. They are made of monomers of monosaccharides joined by bonds that have a range of purposes. They are all insoluable in water.
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What are monosaccharides?
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Monosaccharides such as glucose provide energy from the cell. Frutose and Galactose are also monosaccharides.
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What are disaccharides?
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Disaccharides such as sucrose are made of two monosaccharides joined by a bond, provide both energy and energy storage for the cell.
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What is starch?
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Starch is a spiral shaped structure and is used from energy storage in plants.
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What is cellulose?
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Cellulose has a fibrous, parallel structure and is a structural polysaccharide found in cell walls.
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What is glycogen?
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Glycogen in a branched structure, is used as energy storage in animals.
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What is chitin?
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Chitin has chains of disaccharide molecules which lie beside similar chains. Chitin makes up the exoskeleton of insects and is the main component of the cell wall of fungi.
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What is a nucleic acid?
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Nucleic acids are molecules made of the elements carbon, hydrogen, oxygen, phosphorous. The monomer of a nucleic acid is a nucleotide.
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What is a nucleotide made up of?
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A nucleotide is made up of a sugar (ribose or deoxyribose), a phosphate and a nitrogenous base (uracil, adenine, thyamine, guanine and cytosine)
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What is DNA?
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DNA is a nucleic acid, with two anti-paralell strands forming a double helix. It is found in the nucleus of cells. It carries the genetic code of the cell. It contains the sugar deoxyribose and the bases adenine, thyamine, guanine and cytosine.
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What is RNA?
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RNA is single stranded; it contains a ribose sugar and does not contain the base thyamine, replacing it with uracil. RNA transcribes (copies) and translates the genetic code. RNA transfers infomation from DNA to the cell. It exists as Messenger RN (mRNA) and Transfer RNA (tRNA)
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What is a lipid?
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Lipids are molecules made of carbon, hydrogen and oxygen, however they have less hydrogen and oxygen then a polysaccharide. They are generally known as fats, oils and waxes. Lipids are generally non-polar in nature and are hydrophobic- water hating. They have no recognised monomer.
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What is the function of a ribosome?
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It is the site of protein synthesis. Freefloating are for local use rough endoplasmic reticulum for transport to the golgi body to be packaged for export out of the cell via the secretory vesicles.
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What is the function of the smooth endoplasmic reticulum?
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The smooth endoplasmic reticulum is the site of lipid synthesis.
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What are triglycerides?
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Triglycerides are one type of fat used for energy and long term energy storage with a single glycerol molecules and three fatty acid tails. They also provide insulation and protect vital organs.
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What are phospholipids?
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Phospholipids are another important fat with a phosphate head, glycerol and two fatty acid tails, however the head is hydrophilic, water loving and the fatty acid tails hydrophobic, water hating. Phospholipids are an integral part of the plasma membrane.
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What are steriods?
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Steriods are another lipid molecule used for communication between cells.
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What is cholesterol an important lipid?
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Cholesterol an important lipid becuase is helps to maintain a level of rigidy in cell membranes.
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What are proteins?
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Proteins, otherwise known as polypeptides are made up of the monomer animo acids. These are joined at a ribosome to form a protein. Each amino acid has the same basic structure, with the R group determining which of the 22 amino acids it is.
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What structural elements do proteins make up?
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Proteins make up structural elements such as, eg: keratin, collagen, catalysts (enzymes), haemoglobin, communication (hormones such as insullin), defence (cell surface), receptors and antibodies.
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What are vitamins?
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Vitamins are a group of organic compounds that occur in minute quantities in food. They are essential for many of the chemical reactions that occur in cells. Vitamins are either fat soluable (A,D,E & K) or water soluble.
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What are minerals?
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Minerals are inorganic ions required by both animal and plant cells. They play a role in metabolic processes and are incorperated into many structures produced by cells.
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What are enzymes?
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Most enzymes are proteins. They are biological catalysts. Catalysts are chemicals which increase the rate of chemical reactions. They act on one or more compounds called the substrate. Enzymes go through chemical reactions unchanged but lower the activation energy required to drive a chemical reaction.
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What is the lock and key model?
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The lock and key model suggests that the substrate was simply drawn into the cleft on the enzymes. The substrate and enzyme active site have complementary shapes.
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What is the induced fit model?
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The shape of the enzymes changes when the substrate fits into the cleft. The shape of the active site changes to accomodate the substrate.
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What are the catabolic reactions?
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Some enzymes can cause a single substrate molecule to be drawn into the active site. Chemical bonds are broken, causing the substrate molecule to break apart to become two separate molecules. Thus, energy (ATP) is created. This is also called an exergonic reaction, eg: digestion and cellular respiration
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What are anabolic reactions?
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Some enzymes can cause two substrate molecules to be drawn into the active site. Chemical bonds are formed, causing the two substrate molecules to form bonds and become a single molecule. Thus energy (ATP) is required. This is also called an endergonic reaction, eg: protein synthesis and photosynthesis
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What effects enzyme and their functioning?
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Enzymes are sensitive molecules. They often have a narrow rnage of conditions under which they operate properly. For most of the enzymes associated with animal and plant activity there is little activity at low tempreture. At high tempretures or at the inappropriate pH the shape of the enzymes is altered and it ceases to function (no longer fits into the substrate). This is called denaturing.
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There are four main factors which affect enzyme reaction rate, what are these?
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1. pH levels
2. Tempreture 3. Substrate concentration 4. Enzyme concentraion |
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What is photosynthesis?
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Photosynthesis is the conversion of radiant light energy to chemical energy. Organisms with this ability are called Autotrophic.
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What is the photosynthesis equation?
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6CO2 + 6H2O - light and chlorophyll in excess water - C6H12O6 + 6O2
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What is a grana?
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Chloroplasts are double membrane organelles with an inner membrane folding in stacks.
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What is the stroma?
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The stroma contains chlorophyll and other acessory pigments and they are surrounded by a gel-like material called stroma.
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What is the light dependent stage (light reaction)?
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- Occurs in the grana
- Red and blue light absorbed - Light absorbed by chlorophyll - Energy used to break water molecule - Create 02 (by product) and H+ ions - ATP also produced (used in the second stage) |
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What is the light independent stage (dark reaction)?
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- Occurs in stroma
- Carbohydrate produced - In the form of glucose - Stored as starch - H+ ions and CO2 (from air) combined - ATP from first stage used as energy |
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Why does is the inner membrane of a mitochondia convoluted into folds?
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The inner membrane of a mitochondria convoluted into folds called the cristae in order to increase surface area.
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How does a mitochondia produce energy?
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A mitochondria, to produce energy, breaks down the chemical bonds of glucose to release energy to do work in the cell.
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What is the cellular respiration formula?
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C6H12O6 + 6O2 - 6CO2 +H2O + energy (ATP)
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How do plant cells aerobically cellular respirate?
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They aeobically cellular respirate through:glucose and other carbohydrates made by plants during photosynthesis are broken down by the process of cellular respiration (requires oxygen) in the mitochondria of a cell. This released energy is ATP for the cell.
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What is adenosine triphosphate?
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ATP is the energy molecule used by all cells to do work. ATP is able to store and transport chemical energy within the cells. When the bonds between the last two phosphate molecules are broken, energy is released for the cells to use.
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What is glycolysis?
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In the cytoplasm glucose is broken down to for pyruvic acid molecules. This occurs without the need for oxygen.
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Without oxygen availible how does respiration differ?
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If oxygen in availible the pyruvic acid is broken down to form CO2 + H2O + 36-38 ATP (energy). This occurs in the mitochondria of all living organisms and is called aerobic respiration.
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What are the two types of anaerobic respiration?
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Plants/Fungi/bacteria (fermentation)
- glucose - alcohol (ethanol) + carbon dioxide + energy (2 ATP) Animals - glucose - lactic acid + energy (2 ATP) |
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What is mitosis?
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Mitosis is the process involved in the production of new cells genetically identical with the original cell. The genetic material is replicated and two new nuclei form.
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What is cytokinesis?
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Cytokenisis is the separation of cytosol and the organelles in contains after mitosis.
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What was interphase include?
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G1 - period of cell growth before DNA is duplicated (interphase begins in daughter cells)
S- Period when the DNA is duplicated (that is, when chromosomes are duplicated) G2 - Period after DNA is duplicated. Cell prepares for division. |
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What is prophase?
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Chomosomes become visible. In the late prophase chromosomes appear to be double stranded, held together at the centromere. Centrioles move apart and spindle fibres extend from the centrioles.
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What is metaphase?
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It is the second stage of mitosis, the mitotic spindle fibres are now fully formed and the centrioles are at the two poles of the cell. The double stranded chromosomes (single strand = chromatid) line up around the equator of the cell.
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What is anaphase?
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It is the third stage of mitosis, each centromere divides, so that single stranded chromatids move to opposite ends of the cell and the spindle fibres shorten. This results in one copy of each chromosome moving towards each end of the spindle.
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What is telophase?
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It is the fourth stage of mitosis, the chromatids arrive and the ends of the cells and new membranes from around the new nuclei. The chromosomes disperse and are no longer visible. The spindle fibres also disperse.
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What is the process of cytokenisis?
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Not a part of mitosis, it is the formation of the 2 daughter cells. The membrane pinches together in the middle in order to create two new cells. Each cell has a fill set of genetic infomation, identical to the parent cell, eg: diploid set = 2n)
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What is an autotroph?
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Organisms that given a source of energy (eg: sunlight in plants) can produce their own food from simple inorganic substances; also known as producers. Can produce its own energy.
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What is a heterotroph?
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Organisms that ingest or absorb food in the form of organic material from their environment; also known as consumers. Cannot produce its own energy - must consume something for energy.
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What is digestion?
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Digestion is the chemical breakdown of molecules into smaller units that can pass across plasma membranes.
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Summarise digestion
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Mouth- mechanical breakdown
Silivary Glands- fluids, enzyme addition Oesophagus - travel passage Stomach- chemical and mechanical breakdown Pancreas- enzyme production Liver- bile production Gall Bladder- bile concentration Large intestine- water absorption Anus- expulsion of excess waste Small Intestine- duodenum, jejunum, illeum- breakdown and absorbtion Due to the high concentration of nutrients at the beginning of the small intestine, the nutrients will diffuse through the villi into the lymph and blood vessels. As the nutrients pass further along the intestine, the concentrations decrease and they are transported via active transport. |
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Explain digestion in herbivores?
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For herbivores a mutualistic relasionship helps in the digestion of plant food, cellulose. Herbivores have bacteria in their digestive system that breaks down cellulose into digestible, absorbable units.
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What are the digestive features of a foregut fermenter?
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- Modified stomach or oesphagus used for extended bacterial digestion.
- Bacteria are present in the foregut that breakdown cellulose. -Ruminants are also able to move food from the rumen and reticulum from the stomach back to the mouth for more mechanical digestion. |
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What are the digestive features of a hindgut fermenter?
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- A hindgut fermenter is identified by a large or extended colon or caecum.
- The caecum acts in the exact same way as the rumen in foregut fermenters. - Bacteria able to breakdown cellulose are present in the caecum. |
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What are the digestive features of a nectar and pollen feeder?
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- Nectar and pollen is a very simple biological molecule.
- This means it takes a very short amount of time to be digested and absorbed. - Nectar and pollen eaters have a very short digestive system. |
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What are the digestive features of a carnivore?
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Less time to digest = shorter digestive tract
- carnivores feed exclusively on meat - meat = protain and fat - protein and fat is much for easier to digest than cellulose and therefore less time and energy is required to digest it. |
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What are the four components of blood?
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- Red blood cells
- White blood cells - Platelets - Plasma |
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What is an open circulatory system?
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Blood is pumped by tubular of sac like heart through short vessels into large spaces in the body cavity. The blood bathes the cells beofre re-entering the heart through holes. Muscle action assists in circulation, eg: molluscs and arthropods
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What is a closed single circuit system?
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Blood is contained within vessels and returned to the heart after circulation, eg: fish, sharks and rays. Gases are exchanged through gills.
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What is a closed, double circuit system?
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Occurs in all vertbrates other then fish. Blood is pumped to lungs where it is oxygenated, then returned to heart where it is pumped to the rest of the body. In amphibians and most reptiles the heart is not completely divided and there is some mixing of oxygenated and de-oxygenated blood.
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What is the lymphatic system?
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Fluid leaks out from capillaries and forms tissue fluid. The fluid bathes the tissues, supplying them with nutrients and oxygen and removing wastes. Some fluid returns to capillaries but most drains into a network of vessels. These vessels are one way and cotain valves.
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What is the purpose of lymph nodes?
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They are bean like shaped structures which are scattered throughout the body. As lymph passes through the nodes foreign particles are filtered out and destroyed bu white blood cells.
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What are advantages and disadvantages of gills?
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advantages
- no drying out of respitory surface -CO2 easily diffuses into surrounding water counter-current flow of blood increases rate of gas exchange disadvantages - more energy required to ventilate gills - less O2 in water |
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What are the advantages and disadvantages of the lungs?
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advantages
- less energy required - more O2 in the air disadvantages -loss of water from respiratory surface by evaporation during exhalation |
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What is nitrogenous waste?
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Nitrogenous waste is continually produced as a result of protein breakdown. The main waste is ammonia (NH3). This a highly toxic and soluble compund that must be removed by animals.
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What is a nephron?
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The nephron or uriniferous tubule is the functional unit of the kidney. A nephron consists of a twisted tubule closed at one end, open at the other with a network of associated blood vessels. Each kidney of man is formed of about one million nephrons.
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What is the structure of a nephron?
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Glomerulus: network of capillaries carrying blood under high pressure in the Bowmans capsual.
Bowman's capsule:It is a large double walled cup. It lies in the renal cortex. It contains a tuft of capillaries called glomerulus and the outer wall is continuous with the rest of the nephron. The space between the two walls of the Bowman's capsule is continuous with the lumen of the next part of the nephron. The bowman's capsule and the glomerulus together constitutes the renal corpuscle or malpighian body. PCT: It starts from the neck of the Bowman's capsule and it is highly convoluted. It lies in the renal cortex. The wall consists of a single layer of columnar cells bearing a lot of microvilli on the surface. Loop of Henle: It is a V shaped segment of the nephron located in the renal medulla. It consists of two straight parallel limbs: a descending limb which is a continuation of the PCT and enters into the renal medulla and an ascending limb which reenters the renal cortex and joins the DCT. DCT:It is grea |
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Explain the xylem?
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It is composed of non-living tissue, remnants of cells reinforced with lignin.
Substances involve water and inorganic nutrients. Directions of transport is from the roots up through the leaves. The processes involved are transpiration and root pressure draw water upwards. Capillary action. Passive |
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Explain the phloem?
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Structure, living cels sieve like end plates, companion cells control activities of nucleus free sieve cells.
Substances involve organic nutrients such as sucrose. Direction of transport is from the leaves to the rest of the plant, both directions. Processes involved, requires energy and active transport. |
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How do plants recieve oxygen?
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Openings in the leaves called stomata, allow air to enter the leaf where gas exchange occurs directly with cells by diffusion. Opening and closing is controlled by a pair of guard cells. When guard cells are under water pressure (turgid) they swell and bluckle and the stoma opens. A loss of water (cell becomes flaccid) leads to guard cells becoming straighter and the stoma pores will close.
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Why dont plants have excretory organs?
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-They produce less wastes due to lower metabolic rates
- They are unable to re-use some waste products, eg: CO2 from respiration for photosynthesis -Structurally they have less protein, eg: no muscle, and more carbohydrates, and therefore produce less nitrogenous waste. |
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How do plants manage this nitrogenous waste?
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- Aquatic plants lose wastes directly to the environment
- Terrestrial plants may store waste in: non- living hardwood, leaves that are eventually shed and through storage in the vacuole. |
