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Flashcards by emma_moran, updated more than 1 year ago
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Created by emma_moran
over 10 years ago
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| Question | Answer |
| What does the cytoplasm contain? | The cytosol (intracellular fluid) and the organelles |
| What does the cytosol contain? | Water (75%-90%), glucose, ions, amino acids, ATP, lipids and waste products |
| What is the cytoskeleton? | A network of protein filaments that extend throughout the cytoplasm |
| What are the three main types of cytoskeleton? | Mirofilaments, intermediate filaments and microtubules |
| Where are microfilaments found in the cell? | They surround the edge of the cell |
| What are microfilaments made from? | Actin and myosin |
| What is the role of microfilaments? | Help generate movement (contraction, locomotion and cell division) and provide mechanical support needed for cell strength and shape. They also create microvilli. |
| What is the role of intermediate filaments? | They are very strong and help stabilise the positions of the organelles |
| Where are intermediate filaments found in the cell? | They are found in all parts of the cell subject to mechanical stress |
| What is the structure of microtubules? | Long unbranhed hollow tubules made from tubulin |
| Where about in the cell do microtubules form? | In the centrosome, then radiate outwards |
| What is the role of microtubules? | They help with cell strength, shape and movement of organelles such as vesicles and during division. They also help provide structure to flagella. |
| Where is the centrosome found in a cell? | Near the nucleus |
| What does the centrosome consist of? | 2 centrioles, pericentriolar material that surrounds centrioles and consists of numerous rings of tubulin |
| What are centrioles (found in centrosomes)? | Cylindrical structures composed of a circle of nine clusters of microtubule triplets, both at right angles to each other |
| What is the function of centrosomes? | Growth of mitotic spindle during cell division |
| What is the difference between the centrosome found in a cell not undergoing division and a cell undergoing division? | There is only one centrosome found in a non dividing cell but when the cell begins to divide the centrosome replicates itself early in the process |
| What are cilia? | Numerous, short hair like productions on the cell surface. Each cilium is anchored to a basal body and has a core microtubules enclosed in a membrane |
| What is the function of cilia? | They transport fluid along cell surfaces |
| How does smoking affect cilia? | It destroys cilia, resulting in a build up of mucus, dust and bacteria within the lungs |
| Why are women who smoke at higher risk of an ectopic pregnancy? | Cilia line the fallopian tube and smoking can result in them becoming damaged which prevents the movement the oocyte towards the uterus |
| What are flagella? | Similar structure to cilia but they are longer and only one is found on a cell e.g. sperm cell |
| What is the endoplasmic reticulum? | Network on membranes in the form of flattened sacs and tubules extending from the nuclear envelope into the cytoplasm |
| What are the two types of ER? | RER and SER |
| What is the difference between the RER and SER? | RER has ribosomes attached whereas SER doesn't |
| What happens to the proteins made by the ribosomes when they enter the RER? | They are processed and sorted- enzymes may attach carbohydrate groups or attach the proteins to phospholipids |
| What happens to these proteins when they have been processed and packaged? | They may be incorporated into membranes of organelles or the plasma membrane or, secreted by exocytosis |
| What is the role of the SER? | It has no ribosome but has a greater range of enzymes, making its functions more diverse. It synthesises fatty acids and steroids. In the liver it helps release glucose from gluc-6-p and detoxify lipid soluble drugs such as alcohol and pesticides. Stores Ca2+ ion in muscle. |
| What do ribosomes consist of? | Large subunit and a small subunit that is synthesised separately in the nucleolus. They are rich in ribosomal RNA and contain over 50 proteins. |
| Where are ribosomes found in a cell? | Free in cytoplasm, within the mitochondria and attached to the RER |
| What is the role of the golgi? | It transports proteins from the RER to other regions of the cell |
| What is the structure of the golgi? | It consists of 3-20 membranous cisternae (sac like structures) with bulging edges arranged in a stack. The sacs between are call medial cisternae. |
| Which is the cis face and which is the trans face of the golgi? | The cis face faces the RER (receiving side) and the trans face faces the plasma membrane (exist side) |
| What are the sacs between the cisternae called and what is their role? | They are called medial cisternae and they add carbohydrates and lipids to form glycoproteins and lipoproteins |
| What happens at the cis face of the golgi? | It receives and modifies the proteins |
| What happens at the trans face of the golgi? | Further modifies the proteins and sorts and packages them for their destinations |
| What happens to individuals who repeatedly take drugs such as sedative phenobarbital? | They develop changes in the SER of their liver cells. The cells produce more SER to counteract the poison so the person has to take more of the drug to feel the effect. |
| What is the function of lysosomes? | Digestion of substances entering the cell, worn out organelles (autophagy) and entire cells (autolysis) |
| What is autophagy required for? | Renewal, cellular differentiation, control of growth and tissue remodelling |
| What causes Tay-Sachs disease? | Caused by the absence of a single lysosomal enzyme Hex A. It normally breaks down a glycolipid called ganglioside GM2, especially prevalent in nerve cells. It builds up destroying nerve cell function. |
| What are the symptoms of Tay-Sachs disease? | Seizures, muscle rigidity and blindness. Death normally occurs before the age of 5. |
| What are peroxisomes? | They are similar to lysosomes but smaller and contain oxidases. |
| What is the role of peroxisomes? | They are involved with fatty acid and amino acid metabolism. Oxidise toxic substances such as alcohol. Also contain an enzyme catalase to protect against toxic effects of hydrogen peroxide (made in oxidation reactions) |
| What diseases arise from peroxisomal disorders? | A heterogeneous disease group, with different degrees of severity. This includes Zelweger syndrome, neonatal adrenoleukodystrophy (NALD)and rhizomelic chondrodysplasia (RCDP) |
| What is the role of proteasomes? | Degrade cystolic proteins (unneeded, damaged or faulty). They are important in negative feedback. |
| What causes alzheimers disease? | Build up of misfolded proteins in the brain |
| What is the role of mitochondria? | They are the site of respiration and responsible for the production of ATP |
| What is the role of the cristae in the mitochondria? | Provide a massive surface area for respiration and enzymes needed in respiration are found in the matrix and on the cristae |
| How do mitochondria play an important role in apoptosis? | They release specific chemicals in response to cell stress |
| What are the most common parts of the body affected by mitochondrial disease? | Those with the highest energy demands; brain, muscle, heart kidney and liver |
| What is the structure of the nucleus? | Spherical shaped, surrounded by a double membrane (nuclear envelope) and many nuclear pores that extend through the envelope |
| What does the nucleus contain? | Spherical bodies called nucleoli and there are clusters of DNA and RNA responsible for producing ribosomes |
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