Cell structure - Yr 1 Flashcards
Magnification
the number of times bigger the image/drawing is compared to the object/real size
Resolution
the minimum distance needed to differentiate between 2 adjacent objects
Micrometer
1x10-6 m um
Nanometer
1x10-9 m nm
Light Microscope
A type of microscope which has a condenser, objective lens and eyepiece lens and light is passed through the thin specimen an up through the objective and eyepiece lenses to the eye.
Electron microscope
Beams of electrons are used to visualize structures in a vacuum. Electrons have a smaller wavelength than light so electron microscopes have a higher resolution than light microscopes.
Scanning Electron Microscope (SEM)
A type of electron microscope which bounces beams of electrons off the surface of an object to develop a 3D image of the specimen (no need therefore for thin sections).
Transmission electron microscope (TEM)
A type of electron microscope which asses a beam of electrons through a very thin section of specimen (which often has been stained with heavy metals to show up the fine internal structures).
Cell fractionation
The process where cells are broken up and the different organelles they contain are separated out.
Homogenation
The first stage of cell fractionation when cells are broken up by a homogeniser (blender) and organelles are released from the cell.
Ultracentrifugation
The second stage of cell fractionation when the fragments in filtered homogenate are separated in a machine called a centrifuge.
Graticule
A series of lines on a microscope which can be used to calculate the size of objects.
Eukaryote
A cell that has a membrane-bound nucleus and chromosomes. The cell also possesses a variety of other membrane-bound organelles, such as mitochondria and endoplasmic reticulum.
Organelle
A part of a cell.
Nucleus
Organelle which contains the hereditary material (DNA) which codes for she synthesis of proteins in cytoplasm.
Mitochondria
Organelle where energy is released in aerobic respiration
Chloroplast
Organelle that is the site of photosynthesis
Rough endoplasmic reticulum (RER)
Organelle which provides a large surface area for the synthesis of proteins and glycoproteins and where proteins are transported that are synthesised on ribosomes.
Smooth endoplasmic reticulum (SER)
Organelle where lipids and carbohydrates are synthesized, stored and transported.
Golgi
Organelle that contains a stack of membranes that make up flattened sacs (cisternae) where glycoproteins are synthesized, lipids are transported, modified and stores, proteins are packaged and lysosomes are formed.
Lysosome
Organelle formed when the vesicles produced by the Golgi apparatus contain enzymes. They are where unwanted materials & worn-out organelles are digested.
Ribosome
Organelle made of rRNA and protein where protein synthesis occurs.
Cell wall
Organelle which provides mechanical strength to prevent the cell bursting under the pressure created by the osmotic entry of water, to give mechanical strength. Made of cellulose in plants and chitin in fungi.
Vacuole
Organelle which contains a solution of mineral salts, sugars, amino acids, wastes and sometimes pigments such as anthocyanins. They support herbaceous plants by making cells turgid, may provide a temporary food store and if they contain pigments they may colour petals to attract pollinating insects.
Tissue
A collection of similar cells that perform a specific function.
Organ
A combination of different tissues that are coordinated to perform a variety of functions.
Organ system
Many organs work together in an organ system to perform a particular function.
Prokaryote
A cell of an organism belonging to the kingdom Prokaryote that is characterized by lacking a nucleus and membrane-bound organelles. E.g. bacteria
Bacteria
A prokaryote.
Plasmid
Small circular loops of DNA which contain genes that bacteria can have.
Flagellum
Part of a bacterial cell which helps the bacteria to move.
Virus
Acellular, non-living particles that are smaller than bacteria. They contain DNA or RNA but can only multiply inside living host cells.
Capsid
A protein coat which encloses the nucleic acid in a virus.
Attachment Protein
The capsid can have these which are essential to allow the virus to identify and attach to a host cell.
Daughter cell
The cells that are produced by cell division.
Chromatid
One of the two strands of a chromosome that are joined together by a single centromere prior to cell division.
Centromere
The place where the two copies of DNA after replication are joined together.
Interphase
The period of the cell cycle when the cell is not dividing.
Prophase
The first stage of mitosis when the chromosomes become visible and when spindle fibres develop. The nucleolus disappears and the nuclear envelope breaks down.
Metaphase
The second stage of mitosis when the chromosomes arrange themselves across the equator of the cell.
Anaphase
The third stage of mitosis when the centromeres divide into two and the spindle fibres pull the individual chromatids making up the chromosome apart to their respective, opposite poles of the cell.
Telophase
The fourth stage of mitosis when chromosomes reach their respective poles and become longer and thinner, finally disappearing altogether, leaving only widely spread chromatin. The spindle fibres disintegrate and the nuclear envelope and nucleolus re-form.
Cytokinesis
When the cytoplasm divides.
Spindle fibres
These form the spindle apparatus which are responsible for pulling the chromatids to separate ends of the cell.
Centrioles
Where the spindle fibres develop from in animal cells.
Where the chromosomes arrange themselves during metaphase.
Binary Fission
The process by which cell division occurs in prokaryotic cells.
Cancer
A group of diseases caused by a growth disorder of cells as a result of damage to the genes that regulate mitosis and the cell cycle which results in uncontrolled growth and division of cells.
Tumour
A group of abnormal cells which develops and constantly expands in size.
Plasma Membrane
Membranes consisting of a phospholipid bilayer found around and within all cells. The cell-surface membrane is the plasma membrane that surrounds cells.
Phospholipid
Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule. Phospholipids are important in the structure an functioning of plasma membranes.
Bilayer
A membrane consisting of two layers of phospholipids.
Protein Channel
A protein completely spanning the phospholipid bilayer which form water-filled tubes to allow water-soluble ions to diffuse across the membrane.
Carrier Protein
A protein completely spanning the phospholipid bilayer which bind to ions or molecules then change shape in order to move these molecules across the membrane.
Glycoprotein
Carbohydrate chains attached to a protein (often extrinsic) which are part of the cell surface membrane. They act as recognition sites, help cells to attach to one another and allows cells to recognise one another.
Glycolipid
A carbohydrate covalently bonded with a lipid. They act as recognition sites, help maintain stability of the membrane and help cells attach to one another.
Cholesterol
Lipid that is an important component of cell-surface membranes because it adds strength. Excess in the blood can lead to atheroma.
