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Revision notes on 2.1.5 Eukaryotic Cells for the OCR A Level Biology syllabus, written by the Biology experts at Save My Exams.
How are cells structured? Learn about the size and function of plant and animal cells for GCSE Biology, AQA.
How are cells structured? Learn about the size and function of plant and animal cells for GCSE Biology, AQA.
Oct 8, 2024 · The cell nucleus is a membrane-bound organelle that stores and protects genetic material in eukaryotic cells. It controls the activities of the cell, playing essential roles in gene expression, DNA replication, RNA processing, and transport between the nucleus and cytoplasm. The nucleus consists of the nuclear envelope, nuclear pore complexes ...
- Cell Definition
- Function of Cells
- Cell Types
- Examples of Cells
- Related Biology Terms
- Quiz
Cells are the basic unit of life. In the modern world, they are the smallest known world that performs all of life’s functions. All living organisms are either single cells, or are multicellular organisms composed of many cells working together. Cells are the smallest known unit that can accomplish all of these functions. Defining characteristics t...
Scientists define seven functions that must be fulfilled by a living organism. These are: 1. A living thing must respond to changes in its environment. 2. A living thing must grow and develop across its lifespan. 3. A living thing must be able to reproduce, or make copies of itself. 4. A living thing must have metabolism. 5. A living thing must mai...
Because of the millions of diverse species of life on Earth, which grow and change gradually over time, there are countless differences between the countless extant types of cells. However, here we will look at the two major types of cells, and two important sub-categories of each.
Archaebacteria
As mentioned above, archaebacteria are a very old form of prokaryotic cells. Biologists actually put them in their own “domain” of life, separate from other bacteria. Key ways in which archaebacteria differ from other bacteria include: Archaebacteria’s unique chemical attributes allow them to live in extreme environments, such as superheated water, extremely salty water, and some environments which are toxic to all other life forms. Scientists became very excited in recent years at the discov...
Bacteria
You are most likely familiar with the type of bacteria that can make you sick. Indeed, common pathogens like Streptococcus and Staphylococcusare prokaryotic bacterial cells. But there are also many types of helpful bacteria – including those that break down dead waste to turn useless materials into fertile soil, and bacteria that live in our own digestive tract and help us digest food. Bacterial cells can commonly be found living in symbiotic relationships with multicellular organisms like ou...
Plant Cells
Plant cells are eukaryotic cells that are part of multicellular, photosynthetic organisms. Plants cells have chloroplast organelles, which contain pigments that absorb photons of light and harvest the energy of those photons. Chloroplasts have the remarkable ability to turn light energy into cellular fuel, and use this energy to take carbon dioxide from the air and turn it into sugars that can be used by living things as fuel or building material. In addition to having chloroplasts, plant cel...
Epigenetics– The process by which genes are turned “on” or “off” by adding or removing chemical groups from parts of the chromosome.Eukaryotes– Complex cells with multiple chromosomes and internal organelles such as mitochondria, chloroplasts, and nuclei.Prokaryote– Single-celled organisms with a simple structure, typically having one chromosome and no internal organelles.1. Which of the following is NOT an essential function that all living things must perform? A. A living thing must reproduce. B. A living thing must be able to maintain its internal environment, regardless of external changes. C. A living thing must respond to changes in its environment. D.None of the above. 2. Which of the following is NOT a type ...
Mar 31, 2021 · The endoplasmic reticulum is a network of membranes inside a cell, and its main functions are to process and transport new materials. There are two types of endoplasmic reticulum; the rough ER, and the smooth ER. The rough ER is studded with ribosomes, giving it a bumpy or ‘rough’ appearance.
Many cells in multicellular organisms are specialised. They have specific roles in the organism of which they are part. Their structure is adapted to their function.
