66648
Description
Flashcards by Gemma Bradford, updated more than 1 year ago
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Created by Gemma Bradford
over 12 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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