Cells

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A-Levels Biology f211 Flashcards on Cells, created by Gemma Bradford on 02/05/2013.
Gemma Bradford
Flashcards by Gemma Bradford, updated more than 1 year ago
Gemma Bradford
Created by Gemma Bradford over 11 years ago
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Question Answer
What is a phloem tissue Plant tissue that transports sugars around the plant
What is interphase Where the cell's DNA is replicated to double genetic content, organelles replicated and ATP content increased
Describe the lungs An animal organ that carry out gas exchange, with squamous epithelium tissue in alveoli, ciliated epithelium tissue in the bronchi and elastic connective tissue and vascular tissue in blood vessels
What is mitosis Cell division during the cell cycle, producing 2 new daughter cells genetically identical to original cell
What order are the 4 stages of mitosis 1 - prophase 2 - metaphase 3 - anaphase 4 - telophase
What happens during prophase centrioles move to opposite ends of cell forming the spindle, the nuclear envelope breaks down and chromosomes free in cytoplasm
Describe a leaf A plant organ which carries out gas exchange and photosynthesis, containing palisade tissue, epidermal, and xylem and phloem tissues in the veins
What happens in metaphase Chromosomes line up along middle of cell and attach to spindle by centromere
What is gas exchange Exchange of gases between an organism and it's environment
What happens in anaphase Centromeres divide separating each pair of sister chromatids, they are then pulled to opposite ends of the cell
What is the respiratory system Made up of all organs, tissues and cells involved in gas exchange
What happens at telophase Chromatids uncoil, nuclear envelope forms around each group of chromosomes, cytikinesis occurs dividing the cytoplasm, cell membrane constricts pinching cell into two new daughter cells
What is the circulatrory system Made up of all organs involved in blood supply
Each specialised cell depends on other cells for the functions it can't carry out - give one example of this Muscle cells - need oxygen to do their job, depend on erythrocytes to carry oxygen from lungs to muscles
What are transport systems and give one example Carry substances between different cells - circulatory system helps to move substances around the body in the blood In plants - xylem cells carry water/minerals from root hair cells to palisade cells, and phloem carries sugars around the plant
What are the 3 differences of mitosis in plants compared to in animals 1 - only meristems can divide by mitosis 2 - spindle forms without centrioles 3 - cytokineses begins at centre of a cell with a cell plate
What is a communication system and give one example Allow communications between cells in different parts of an organism - nervous system in animals send electrical signals to different tissues and organs
What is a meristem Mitotically active plant tissue, in areas of a plant that are growing
What is a centriole Small, hollow cylinder containing a ring of microtubules - bundles of protein
What is asexual reproduction Reproduce without sex using mitosis
What is budding The cell swells on one side forming a bud, undergoes interphase and then mitosis, the budding cell then contains a nucleus identical to parent DNA, then cytokineses occurs and bud pinches off from parent cell forming new cell
What is a homologous pair A pair of matching chromosomes with same genes (can have different alleles)
What does diploid mean Each cell contains two of each chromosomes 2n - one from mum, one from dad
What does haploid mean Only one copy of each chromosome in cell
Is a zygote (fertilised egg) haploid or diploid Diploid
Is a gamete (sperm/egg) haploid or diploid Haploid
What is meiosis Cell division in reproductive organs to produce gametes, starting as diploid, turning to haploid
What is a meiosis end product Four haploid daughter cells
What are stem cells Unspecialised cells that can develop into any type of cell
What is differentiation Where stem cells divide to become new cells that become specialised for it's job
What can adult stem cells in bone marrow differentiate into Neutrophil and erythrocyte
What can stem cells in the cambium differentiate into Xylem and phloem
How are erthrocytes specialised for it's function of carrying oxygen in the blood Biconcave disc shape = large surface area for exchange No nucleus = more room for haemoglobin
How are neutrophils specialised for it's function of engulfing foreign pathogens Flexible shape = to engulf Many lysosomes in cytoplasm = digestive enzymes to break down engulfed particles
How are epithelial cells specialised for it's function Cilia = waft particles away from organs Microvilli = folds in cell membrane to increase cell's surface area
How are sperm cells specialised for their function of fertilising an egg cell Flagellum = to swim to egg Many mitochondria = provide energy to swim Acrosome = digestive enzymes to penetrate surface of egg
How are palisade mesophyll cells specialised for their function of photosynthesis Many chloroplasts = absorb sunlight thin walls = shorter diffusion distance for CO2
How are root hair cells specialised for their function or absorbing water/mineral ions from the soil Large surface area = absorption Thin permeable cell wall = entry or water/ions Many mitochondria = energy for active transport
How are guard cells specialised for their funtion of opening stomata Thin outer walls and thick inner walls = force them to bend outward opening stomata
What is a tissue Group of cells specialised to work together to carry out a function
What is an organ A group of different tissues that work together to perform a function
What is an organ system Organs working together to perform a function
What is a squamous epithelium tissue Single layer of flat cells lining a surface, providing a think exchange surface for diffusion
What is an epithelium A tissue that forms a lining
What is a ciliated epithelium Layer of cells covered in cilia
What are the 4 parts of the cell cycle Mitosis, gap phase 1, synthesis, gap phase 2
What is a xylem tissue Plant tissue that transports water around the plant and supports it
Maximum resolution of light microscope 0.2 micrometres
Maximum resolution of transmission electron microscope 0.0001 micrometres
Maximum resolution of scanning electron microscope 0.005 micrometres
Maximum magnification of light microscope x 1500
Maximum magnification of transmission electron microscope more than x1000000
Maximum magnification of scanning electron microscope less than x100000
What colour do stained electron microscopes produce black and white
What microscope lets you see organelles and their internal structure transmission electron
What is magnification how much bigger an image is than the specimen
What is the formula for magnification length of image/ length of specimen
What is resolution how well a microscope distinguishes between two points that are close together
Do you divide or x by a 1000 to convert from a smaller unit to a bigger unit divide by 1000
What is the difference between DNA in profaryotic and eukaryotic cells Prokaryotic - circular DNA free in cytoplasm Eukaryotic - linear DNA inside nucleus
What is a cytoskeleton protein threads as microfilaments/microtubules running through cytoplasm
What are microtubules tiny protein cylinders
What is a ribosome site where proteins are made
What does partially permeable mean Let some molecules through but not others
What is a lysosome round organelle with digestive enzymes
What is a mitochondrion site of aerobic respiration where ATP is produced
What is in the bilayer proteins, glycoproteins, glycolipids, cholesterol, phospholipids
What is a plasma membrane surface of cells made from lipids and proteins, it regulates movement of substances into and out of cell
How is the bilayer arranged phospholipids have a hydrophillic head and hydrophobic tail, heads face outward toward water on either side of membrane, with tails forming the centre of the bilayer
What can easily diffuse through the membrane small, non-polar substances and water
What does polar mean one end slightly + charge and one end with slightly - charge
How does cholestrol contribute to membranes Gives stability as it binds to hydrophobisctails of phospholipids, causing them to pack closely together
What role do proteins play in the membrane Control what enters and leaves the cell - channel proteins form channels in membrane, carrier proteins transport molecules across membrane, proteins also act as receptors
How to glycolipids and glycoproteins contribute to the membrane Stabilise membrane by forming hydrogen bonds with surrounding water molecules, also act as receptors
What is a target cell A cell that responds to a particular messenger molecule
What is diffusion Net movement of particles down a concentration gradient - from an area of high concentration to an area of lower concentration
What 3 factors affect the rate of diffusion 1 - concentration gradient 2 - thickness of exchange surface 3 - Surface area
What is osmosis Diffusion of water molecules across a partially permeable membrane, from an area of high water potential to an area of lower water potential
What is water potential The likelihood for water molecules to diffuse in/out of a solution
What is the water potential of water 0 - it is high
What will have a negative water potential Solutes - anything that is not pure water
What is an isotonic solution Where two solutions have the same water potential - so no net movement of water
What is a hypOtonic solution Where the solution has a higher water potential than the cell
What is a hypERtonic solution Where a solution has a lower water potential than the cell
What is plasmolysis Where the cytoplasm and plasma membrane of a plant cell pull away from cell wall
What is facilitated diffusion Diffusion of large molecules down a concentration gradient using channel and carrier proteins
What is active transport Diffusion against a concentration gradient, using carrier and channel proteins and energy from ATP
What is endocytosis Where a cell surrounds a substance with the plasma membrane, pinching off to form a vesicle inside the cell
What is exocytosis Where vesicles pinch off from golgi sacs and fuse with plasma membrane to release contents outside of cell
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