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Flashcards by Olivia Hall, updated more than 1 year ago
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| Question | Answer |
| magnification= | image size ---------------------- actual size |
| define resolution? | the ability to distinguish between 2 separate points clearly. |
| define magnification? | The state of something being magnified or represented by an amplified image. |
| outline the roles of the cytoskeleton? | -keeps the cells shape -allows movement of organelles -supports the cell |
| role of vesicles? | -membrane bound sacs found in cells - transport many different materials around the cell |
| role of nucleus? | -houses genetic info -contains chromatin that condenses during mitosis. -nucleolus makes RNA and ribosomes. |
| structure of RER? | -flattened sacs called cisternae. -joined to the outer nuclear memb. -littered with ribosomes that make proteins. |
| structure of SER? | -same as RER without ribosomes |
| role of vesicles? | -transports molecules around cell. |
| role of SER? | -involved in making lipids that the cell needs |
| role of Golgi? | role: receives proteins from the ER and modifies them by possibly adding a sugar mol. then packages the modified proteins into vesicles that can be transported. some modded proteins go to the cell surface to be secreted out. |
| role of mitochondria? | role: produces the energy that drives the cells (ATP) |
| role of chloroplasts? | role: site of photosynthesis, light energy used to drive reactions of photosynthesis, carbohydrate mol are made from carbon dioxide and water. -found on thylakoid memb and in intergranal memb. |
| role of lysosomes? | role: contain powerful digestive enzymes. used to break down pathogens ect. |
| structure and role of ribosomes? | structure: some are free in cell and some bound to RER. role: site of protein synthesis, act as assembly line where coded info from mRNA is used to assemble proteins from amino acids. |
| outline roles of membranes | -separating cell contents from the outside environment -separating the cell components from cytoplasm. -cell recognition and signalling. -holding the components of some metabolic pathways in place. -regulating the transport of materials into or out of the cell. |
| define diffusion? | diffusion is the movement of molecules down a concentration gradient. (from an are of high concentration to an area of low) |
| define active transport? | active transport is the movement of molecules against its concentration gradient with the use of an energy source such as Adenosine tri-phosphate (ATP) |
| what effects the rate of diffusion? | -temperature -concentration gradient -distance -size of molecules -movement/stirring -surface area |
| what are the dis-advantages of having genetically identical crops? | -same genetics means that adapted viruses/ crop deceases will be able to destroy the whole population as there is little diversity in genetic info. |
| pros of plants being able to reproduce asexually? | asexual means that plants can reproduce quickly even when there are no other plants around to reproduce with. asexual reproduction saves the energy associated with flowers, fruit and seed production. |
| multicellular organisms need transport systems why? | -have a small SA/VOL ratio -not all cells in contacts with external medium. -tissues, organs are created to allow delivery of oxygen and removal of carbon dioxide. |
| define differentiation? | when a cell takes on a particular role/function |
| how can cells adapt to become differentiated? | -increase the number of certain organelles within the cell. -change the shape of the cell -some of the contents of the cell. |
| role of neutrophils in body? | is to ingest invading micro-organisms that are recognised as foreign by the antigen presenting cells (macrophages) |
| define tissues? | collection of cells working together to perform a common function. |
| define organ? | collection of tissues working together to perform a particular function. |
| define organ systems? | number of organs working together to perform an overall function. |
| outline the xylem tissue structure | -xylem vessels with parenchyma cells and fibres. -walls reinforced/waterproofed with deposits of lignin. -ends of the cells making the xylem break down forming a long continuous tube with wide lumen. -where lignin isn't present are sunken pits (allow water molecules to move into live tissue cells around the xylem) |
| outline the phloem tissue structure | -sieve tubes and companion cells. -ends don't fully break down. (form sieve plates) - sieve plates allow movement of materials up & down tubes. -companion cell is very metabolically active -there actives play important role in movement of products produced from photosynthesis up and down the plant in the sieve tubes. |
| give 2 examples of epithelial tissues | -squamous epithelial -ciliated epithelial |
| give 2 examples of connective tissues | -cartilage -bone & blood |
| list requirements for photosynthesis | -light -carbon dioxide -water -chlorophyll presence |
| how are leaves adapted for photosynthesis? | -transparent upper surface layer to allow more light through. - a layer of cylindrical palisade cells (packed with chloroplasts containing chlorophyll) -loosely packed spongy mesophyll layer with many gaps for air flow -lower epidermis has pores called stomata, allows gasses to be exchanged between leaf and air. -2 guard cells swell to open the stomata. (turgid-open vice versa) -leaf vein system stansports H20 to leaf and takes products from pho-syn-sis away to other parts of plant. |
| why do plants need water in their leaves? | -cells need to be turgid to be metabolically active - photosynthesis requires water to produce carbohydrates |
| why is it important that products of photosynthesis is transported up & down plant? | - allows carbs to reach growing leaves/shoots to aid growth |
| how does SA:VOL ratio effect diffusion? | -- |
| define exchange surface? | an exchange surface is something that is used to allow transfer or substances. e.g. alveoli in lungs |
| why do large organisms need special exchange surfaces? | -need alot of oxygen for respiration -cannot supply enough through their skin surface as SA:VOL ratio is too low |
| what makes an exchange surface efficient? | -large SA: more space for molecules to diffuse. -thin barrier: short diff distance -permeable membrane: to allow molecules through. -good supply of molecules to exchange surface: keeps conc high so diff grad is high. -removal of molecules from other side: keeps conc of molecules low so diff grad high |
| list the things that make up the gas exchange system | -trachea (has cartilage in C shape to allow flexability and support) -bronchi (has less cartilage,breaks off into 2 separate bronchioles) -lungs -alveoli (exchange surface) -external intercoastal muscles (contract to lift up the ribs) diaphragm (relaxes and contracts to increase/decrease volume of lungs. |
| role of cartilage? | -supports trachea and bronchi -prevents collapse -flexability -allows the oesophagus to expand during swallowing. |
| role of smooth muscle? | -can make lumen of airway narrower (bronchioles) -can help prevent harmful thing sin the air form entering the alveoli by contraction in the bronchioles. |
| role of elastic fibres? | smooth muscle contracts so does the elastic fibres -smooth muscle recoils so does the elastic fibres (helps to increase the lumen of airway) |
| define tidal volume? | amount of air able to move in or out of lungs in a single breath at rest. (allows removal of co2 and enough oxygen to support its resting o2 needs.) |
| define vital capacity? | largest vol of air that can be removed from the lungs in one complete breath. |
| define residual volume? | this is the amount of air that is left in the lungs after the max exhalation of person. |
| define inpiratory reserve volume | is how much more air can be breathed in over and above the normal tidal volume when you take a big breath. (needed when exercising) |
| define expiratory reserve volume | how much more air can be breathed out over and above the amount that is breathed in a tidal volume breath. |
| what is a double circulatory system? | when the blood passes through the heart 2 times in a single circulation. |
| list features of a good transport system? | -medium -pump -exchange surface -tubes/vessels |
| what is an open circulatory system? | blood flows freely in the small animal as it doesn't need the transport system like larger animals. muscles usually force the movement of the blood around the animal. |
| what is a closed circulatory system? | a closed circulatory system is when blood is held in the capillaries. moved around using a pump. |
| which side of the heart pumps deoxygenated blood away form the heart? | right side |
| which side of the heart pumps blood to the rest of the body? | left side (reason the left ventricle is thicker than the right) |
| in what section of the heart is the atrioventricular valves located? | between the atria and ventricles |
| what makes up the artery? | -lumen -endothelium -smooth muscle -collagen fibres -elastic fibres. |
| what makes up the vein? | -lumen -endothelium -elastic fibres -smooth muscle -collagen fibres |
| what makes up the capillary? | -lumen -endothelium |
| role of elastic tissue? | allows the wall to stretch and recoil when the heart pumps. |
| role of tissue fluid? | transports O2 & nutrients from the blood to the cells. -transports CO2 and waste back to the blood. |
| when haemoglobin binds to oxygen it becomes? | oxyhaemoglobin |
| how are hydrogen carbonate ions formed? | -carbonic acid catalysed by carbonic anhydrase. -CO2+H2O=(H2CO3) -carbonic acid dissociates to release H+ ions = (HCO3-) -(H2CO3--HCO3- & H+) -H+ joins Hb -- (HHb) -chloride ion shift into cell to maintain a neutral cell. |
| what is the Bohr effect? | -the Bohr effect is the process of having large quantities of CO2 in repairing tissues causing the erythrocyte to release even more oxygen. |
| what is the appoplast pathway? | water passes through the water filled spaces between cellulose molecules. does not pass through any plasma membranes. |
| what is the symplast pathway? | passes through the plasmodesmata, (gaps in the cell wall that contain a thin strand of cytoplasm). |
| what is the vacuolar pathway? | not confined to cytoplasm, able to pass through the cells and vacuoles. |
| how does water travel up the stem? | -root pressure -tranpiration stream -capillary action |
| how does H2O leave the leaf? what does evaporation cause? | -usually the H20 will leave through the stomata that open when the guard cells are fully turgid. -the evaporation of the cells creates a water potential gradient and so water from surrounding cells move water over through osmosis. (transpiration stream) |
| define transpiration? | the loss of water from the upper section of the plant particularly the leaves. |
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