Btec Applied Science Unit One Biology, Questions and answers, 100% Accurate. Graded A+

Btec Applied Science Unit One Biology, Questions and answers, 100% Accurate. Graded A+ What is the function of the mitochondria? - -cellular respiration What is the function of the ribosomes? - -protein synthesis What is the function of the smooth endoplasmic reticulum? - -Synthesis and transport of lipids and carbohydrates What is the function of the Golgi apparatus? - -Modified and packaged proteins into vesicles for transport What is the function of the lysosomes? - -Digests old cell material and waste What is the function of the centrioles? - -Form into spindle fibres for cell division What is the function of the chloroplasts? - -photosynthesis What is the function of the tonoplasts? - -The membrane around the vacuole to keep it together What is the function of the vacuole? - -Maintain turgid pressure in the plant cell What is the function of the plasmodestmata? - -To allow materials to pass through the cell wall What is the function of the amyloplasts? - -Starch synthesis and storage Name three organelles which are only in plant cells - -Vacuole, chloroplasts, cell wall Define eukaryotic cells - -Are part of a multicellular organisms Define prokaryotic cells - -Are unicellular organisms Name two differences between eukaryotic and prokaryotic cells? - -Eukaryotic has a nucleus but prokaryotic doesn't my eukaryotic has a membrane bound organelles while prokaryotic doesn't What two dyes are used to show gram positive and gram negative bacteria? - -Crystal violet and safranin Describe the difference between gram positive and gram negative? - -Gram negative has thin cell walls so the ethanol washes out the crystal violet, so they appear safranin pink. Gram positive appears purple Describe the key features of a sperm cell? - -Across one to penetrate the egg, tail for swimming, lots of mitochondria for energy Describe the features of egg cells? - -Hormones to attract the speed, zona pellucuda to protect the egg, corona radiate to supply protein to developing foetus What is TEM? - -Transmission electron microscope What is SEM? - -Scanning electron microscope Compare TEM and SEM - -TEM produces images of thin slices of material whereas SEM looks at the surface topography. Both are very magnified compared to the light microscopes and require dead samples. Describe how a light microscope works - -Light microscopes use visible light and magnifying lenses to observe small objects Describe how an electron microscope works - -They use a beam of electrons in a vacuum with a wavelength of less than 1 nm to visualise the specimen Give one positive and one limitation of light microscopes - -Positive - can observe living structures Negative - relatively low magnification (x500) and resolution (x200nm) Give one positive and one negative of electron microscopes - -Positive - high magnification (x) and resolution (0.1nm) Negative - destroys the sample Magnification equation - -magnification = image size/actual size Describe the key features of a palisade cell - -Found in leaves, they are rectangular box shaped cells that contain chloroplasts. The chloroplasts can absorb light for photosynthesis. Chloroplasts move around in the cytoplasm to maximise the amount of light absorbed Describe the key features of a root hair cell - -Found in a plants roots near the growing tip. They have long hair like extensions called root hairs. They increase the surface area of the cell to maximise the movement of water and minerals. Describe the key features of a red blood cell (erythrocytes) - -Biconcave in shape increases the surface area to volume ratio. They are flexible so that they can squeeze through the narrow capillaries. They have no nucleus, this increases space for haemoglobin to carry oxygen Describe the key features of white blood cells (neutrophils) - -Multi-over nuclei which help them to squeeze through small gaps when travelling to the site of infection. Cytoplasms holds lysosomes that contain enzymes which breakdown pathogens and then ingest them Describe the location of the squamous epithelial tissue - -Lines organs Describes the function of the squamous epithelial tissue - -It is one cell thick and forms thin, smooth, flat layers, ideal for rapid diffusion Describe the location of the ciliated columnar epithelial tissue - -Lines the trachea Describe the function of the ciliated columnar epithelial tissue - -It is column shaped cells with hair like structures (cilia) along the surface. They protect the lungs by sweeping away pathogens and secreting mucus to trap the pathogens Describe the location of the endothelial tisuue - -Lines the heart and blood vessels Describe the function of the endothelial tissue - -The cell provides a short diffusion pathway for substances such as products of digestion into the blood How is emphysema caused? - -Smoking can irritate and cause the epithelial tissue of the lungs to become inflamed and scarred. The alveoli walls become thicker and produce more mucus. This damage caused the lungs to lose their elasticity How is atherosclerosis caused? - -Carbon monoxide and high blood pressure can damage the inner lining of arteries. White blood cells repair the damage and encourage muscle and fatty substances to build up under the endothelial tissue rather than on the surface. This can decrease the size of the lumen and cause the heart to work harder What is the function of the skeletal muscle - -It is attached to bones and controls contraction and relaxation What is the function of the cardiac muscle - -It is found in the heart, it contracts to make the heart beat What is the function of the smooth muscle - -It is found in the walls of hollow organs Describe when slow twitch muscle fibres are used and why - -Good for marathon runners More effect it is at using oxygen to generate energy (ATP) for continuous and extended muscle constructions over a long time Describe the makeup of slow twitch muscle dibres - -Less sarcoplasmic reticulum More mitochondria More myoglobin Dense capillary network Release ATP slowly by aerobic respiration What is a fast twitch oxidative muscle fibre? - -These are similar to slow twitch but they are able to hydrolyse the ATP more quickly and contract quicker. They are relatively resistant to fatigue. What is a fast twitch glycolysis muscle fibre? - -These have less myoglobin, mitochondria and capillaries. They have large concentration of glycogen a valuable for anaerobic respiration. They contract quickly but also fatigue What is an action potential? - -Electrical impulse that travels down the axon triggering the release of neurotransmitters What is the resting potential of a neuron? - -A neuron is not is not transmitting an action potential and is at rest What is the myelin sheath? - -covers the axon of some neurons and helps speed neural impulses What are Schwann cells? - -A type of cell that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system How is an action potential generated? - -As an action potential travels down the axon, there is a change in polarity across the membrane. The Na+ and K+ gated ion channels open and close as the membrane reaches the threshold potential, in response to a signal from another neuron. What is depolarisation? - -An electrical state whereby the inside of the cell is made less negative relative to the outside than at the resting membrane potential. A neuron membrane is depolarised if a stimulus decreases its voltage from the resting potential of -70mV in the direction of zero voltage. How does a nerve impulse cross a synapse? - -When the impulse reaches the end of the neuron it crosses the synapse in the form of a chemical neurotransmitters. It diffuses across the synapse and initiates an action potential in the next neuron Two structural features that are found in only animal cells - -Centriole, cilia What is the function of nucleolus? - -Makes RNA and ribosomes What is the function of the nucleus? - -Where DNA is stored and the control centre of the cell What is the meaning of the specialised cell? - -A cell becomes specialised when it's structure is altered. This enables a cell to have a specific function. This process is called cellular differentiation How the structure of a neutrophil enables it to exit the capillary in order to reach the bacteria? - -It has a flexible nucleus this makes it fit through the pores and squeeze into smaller spaces What is the function of lysosomes in a neutrophil? - -They contain enzymes which are used to break down bacteria What is the structure of the myelin sheath? - -Contains your Schwann cells, the cells are flattened, it has little cytoplasm, high fat content, contains a nucleus Why the speed of conduction is slower in non-myelinated neurones than in myelinated neurones - - There is a lack of insulation in the non-myelinated neurones, which causes the impulse unable to jump across or that there is a loss of iron or shielding Smokings different risk factors - -Addictive Nicotine can damage endothelial cells and carbon dioxide Certain toxins in tobacco can lower the high density cholesterol Carbon monoxide can get stuck in red blood cells so less oxygen is moving around the body because of red blood cells being stuck Name the three types of muscle tissues - -Skeletal, cardiac and smooth What are the two protein filaments found in muscle cells? - -Thin actin Thick myosin What are the conditions like inside and outside of the cell when the neurone is at rest? - -The electrical charges on the outside has a positive charge and the inside has a negative charge What ions enter the cell at the synapse - -Ca2+ What is magnification? - -the ratio of an object's image size to its real size What is a prokaryotic cell? - -It's a bacteria cell What is an organelle? - -It's specialised structures found within a living cell What is resolution? - -It's the ability to distinguish between objects that are close together What is an eukaryotic cell? - -It is an animal and plant cell What is the structure of the plasma membrane? - -Composed of a phospholiprobilary with proteins embedded in the layers What is the structure of the cytoplasm? - -Is a thick, gelatinous, semi-transparent fluid What is the structure of the nucleus - -The largest organelle and is surrounded by a nuclear envelope. The envelope has nuclear pores which allow the movement of molecules through it. The nucleus contains chromatin What is the structure of the nucleolus? - -Dense spherical structure in the middle of the nucleus What is the structure of the rough endoplasmic reticulum? - -Network of membrane bound flattened sacs called cisternae studded with ribosomes What is the structure of the smooth endoplasmic reticulum? - -Network of membrane bound flattened sacs called cisternae, with no ribosomes What is the structure of the Golgi apparatus? - -A stack of membrane bound flattened sacs What is the function of the vesicles? - -Transport vesicles are used to transport materials inside the cell and secretory vesicles transport proteins that are to be released from the cell, to the cell surface membrane What is the structure of the vesicles? - -Small spherical membrane bound sacs with fluid inside What is the structure of lysosomes? - -Small spherical membrane bound sacs containing hydrolyric enzymes What is the structure of ribosomes? - -Tiny organelles attaches to rough ER or free floating in the cell. They consist of two sub units and they are not surrounded by a membrane What is the structure of the mitochondria? - -They have two membranes. The inner membrane is highly folded to form Cristae. The central part is called the matrix. They can be seen as long in shape or spherical depending on which angle the cell is cut at What is the structure of the centrioles? - -They are small tubes of protein fibres What is the structure of the cell wall? - -Made of cellulose forming a sieve like network What is the function of the cell wall? - -Protects and supports each cell and the whole pl