A solar cell (also called photovoltaic cell or photoelectric cell) is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect. Assemblies of cells used to make solar modules which are used to capture energy from sunlight‚ are known as solar panels. The energy generated from these solar modules‚ referred to as solar power‚ is an example of solar energy. Photovoltaics is the field of technology and research related to the practical
Premium Solar cell
The fluid mosaic model of the cell membrane. What is the fluid mosaic model? The fluid mosaic model is a model conceived by S.J. Singer and Garth Nicolson in 1972 to describe the structural features of biological membranes. The membrane is described to be fluid because of its hydrophobic integral components such as lipids and membrane proteins that move laterally or sideways throughout the membrane. That means the membrane is not solid‚ but more like a ’fluid’. The membrane is depicted as mosaic
Premium Protein Cell membrane Membrane biology
Chapter 2 IB Biology 2.1 Cell Theory 2.1.1 Outline the cell theory (2). • All organisms are composed of one or more cells • Cells are the smallest units of life • All cells come from preexisting cells • TOK: cell theory replaces the former ideas of spontaneous generation or abiogenesis in which inanimate matter assembles itself into living forms • Exception: muscle cells- more than 1 nucleus‚ very long; (fungal cells) hyphae roots- not a single unit; protoctista- not specialized to single
Premium Cell Cell membrane
Explain. Every cell contains organelles‚ the structures that carry out their specific functions. Organelles are also known as cell compartments. Eukaryotic cells have membrane bound compartments in which specific metabolic activities takes place. The organelles of the prokaryotes are not membrane bound and are simpler structures. Just like organs‚ each organelle contributes in its own way to help the cell function well as a whole. The organelles are endoplasmic reticulum‚ golgi apparatus‚ mitochondrian
Premium Eukaryote Organelle Cell
Introduction The current method of cell expansion using T25 flasks for human embryonic stem cells (hESCs) have been proven to be extremely time and space consuming‚ labour intensive and difficult for scale-up (Minimal of 200 T25 flasks needed). It is estimated 2.8x108 - 5.6x108 undifferentiated hESCs are required by the end of the expansion stage for the process to work‚ as at least 5x107 cells of well differentiated post-mitotic Nrl+/Crx+ precursors are needed for transplant (Maclaren et al‚ 2006)
Premium Stem cell Cell culture Cellular differentiation
shows the level of hemoglobin measured in two different groups of athletes. Hemoglobin / grams per 100 cm3 Number of athletes tested Standard deviation / grams per 100 cm3 Group A 12.6 200 0.8 Group B 11.9 220 3.2 Which of the following statements is correct? A. Results from group B are more accurate because more athletes were tested. B. Results from group B are more reliable because it has a higher standard deviation. C. More athletes have their hemoglobin concentration close to
Premium DNA
Cell wall is a fairly rigid‚ protective and supportive layer surrounding the cell external to plasma membrane of plants‚ bacteria‚ archaea‚ fungi and algae. It is absent in animals and most protists. It was first observed by Robert Hooke in 1665. It is not an entirely rigid structure as the cell wall expands due to the growth of the cell. It varies in thickness from o.1mm to I0mm.in most of the cells‚ cell wall is present from the very beginning to the last‚ but in slime molds (myxomycetes)
Premium Cell wall
Organelle | Found In | Structure | Function | Cell Membrane (plasma membrane) | Both | A phospholipid bilayer that contains proteins. Lipids face each other while the phosphates face away from each other. Most proteins stay with the outer layer of phospholipids. | Protective barrier. Transports required materials and wastes in and out of the cell. Cell communication. | Nucleus | Both | Dense sphere inside the cell. Surrounded by a nuclear envelope with nuclear pores that allow for material transportation
Premium Cell Organelle
2006 STRUCTURE AND FUNCTION IN CELLS Achievement Standard 90464 – Biology 2.8 – Describe cell structure and function TYPES OF CELLS • PROKARYOTIC CELLS = more primitive‚ unicellular‚ have no organised nucleus‚ no membrane-bound organelles‚ genetic material is 1 circular DNA molecule‚ can have tiny extra rings of DNA called plasmids‚ all have cell walls e.g. bacteria and blue-green algae • EUCARYOTIC CELLS = unicellular or multi-cellular‚ plant and animal cells‚ have a nucleus
Free Cell Eukaryote Organelle
level of chromosomes‚ by the Belgian zoologist Edouard Van Beneden‚ in Ascaris worms’ eggs. The significance of meiosis for reproduction and inheritance‚ however‚ was described only in 1890 by German biologist August Weismann‚ who noted that two cell divisions were necessary to transform one diploid cell into four haploid cells if the number of chromosomes had to be maintained. In 1911 the American geneticist Thomas Hunt Morgan observed crossover in Drosophila melanogaster meiosis and provided the first
Premium Meiosis Gamete Mitosis