Biology Flashcards
Osmosis
Water moves from where the solute is in low concentration to where the solute is in high concentration through a semipermeable membrane.
Diffusion
Movement of a substance from high concentration to low concentration [no membrane involved, free movement of substances - particles spread out]
Active transport
Requires the input of energy. Moves molecules from an area with low concentration to an area with high concentration.
Passive transport
Does not require energy to move substances across cell membranes. Moves molecules from a high concentration to a low concentration.
Endocytosis vs Exocytosis
Endocytosis is when a large particle has to be moved into a cell and the cell membrane changes it’s shape to surround the particle.
Exocytosis is when substances are transported to the external environment of the cell.
Structural adaptation
physical features or characteristics that have helped them survive in an environment eg. root structure, leaves, fur, scales.
Physiological adaptations
Internal features of an organism that helps them survive. Eg. poison leaves, snake and spider venom.
Behavioural adaptations
Something a plant or animal does in order to survive. Eg. growing towards the sunlight, roots growing down, migration, hibernation.
Stomata structure and function
Miniature pores called stoma that are surrounded by a pair of guard cells. It allows the plant to take in carbon dioxide and let out oxygen by regulating gas exchange between the plant and environment.
Antibiotic resistance
Through mutation and selection, bacteria can develop defense mechanisms against antibiotics.
Cane toad evolution
No natural predators for cane toads causing them to adapt to the environment.
Darwins observations
He discovered various different species of finches that varied from island to island. In his observations, he realised that the shape of their beaks were different according to the food they consume
Evolutionary theory evidence
Fossils and similarities between related organisms were used by Darwin. Scientists today use DNA testing.
Eukaryotic cells - what is it
can be single celled or multicellular, contains a nucleus surrounded by a membrane.
Prokaryotic cells - what is it
Single celled organism, no membrane-bound nucleus or membrane-bound organelles.
Biotic
The living parts of an ecosystem such as plants, animals and bacteria
Abiotic
The non living parts of an ecosystem such as water, soil and atmosphere
Photosynthesis
The plant draws up water through the roots, the leaves take in carbon dioxide from the air, leaves trap energy from the sunlight, the plant uses the energy from the sunlight to turn water and carbon dioxide into oxygen, the plant uses oxygen for growth.
Respiration
The transfer of oxygen from the outside environment to cells within tissues as well as the removal of carbon dioxide.
Enzymes - how do they work and what affects their actions
They are protein molecules that control all metabolic reactions in living cells. Enzymes require particular conditions in order to work effectively (normal body temp).
Transport systems in animals and plants
Plants - Uses xylem and phloem tissues for transportation of minerals and water.
Animals - The cells require a constant supply of nutrients and oxygen and the continual removal of waste products. A circulatory system is the most efficient way to achieve this. (use their blood to transport carbon dioxide and oxygen.)
Xylem
Transports water and dissolved minerals upward through the plant, from the roots to the leaves.
Phloem
Transport products of photosynthesis from the leaves, where they are produced, to the rest of the plant where they are either used or stored.
Concurrent/countercurrent flow for gas exchange
Concurrent - Where the blood flows next to the medium (liquid) in the same direction. As they flow along the membrane, oxygen moves to equilibrium
Countercurrent - Blood flows in the opposite direction to water, next to the water that has given up less of its oxygen. This way, the blood absorbs more and more oxygen as it moves along
Autotrophs vs heterotrophs
Autotrophs: an organism that can produce its own food using light, water, carbon dioxide or other chemicals.
Heterotrophs: an organism that eats other plants and animals for energy and nutrients.
Convergent evolution
Distantly related organisms independently evolve similar traits to adapt to similar necessities.
Divergent evolution
Two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental pressures.
Punctuated equilibrium
Evolution occurs through short bursts of intense speciation followed by long periods of no change.
Kidney function
Removes waste from the blood, Regulates concentration of substances and Maintains homeostasis.
Gas exchange in plant and animal cells
Plants: gas exchange takes place through the stomata. Plants take in carbon dioxide and release oxygen through the stomata
Animals: release carbon dioxide into the atmosphere and take up oxygen
Thermoregulation
Maintains a steady internal body temp despite changes in the external condition
Cell differentiation
Dividing cells change their functional or observable traits type.
Comparative anatomy
This is the study of similar and different structures in an organism. An example is the similar bone structure in the forelimbs of cats, bats, whales and humans.
The three main structures include - homologous structure, analogous structure, vestigial structure
Functions of a cell membrane
To protect the cell by acting as a barrier and to control the entry and exit of materials from cells.
Mitochondria function
Produces energy through cellular respiration. Sugars, fats and other fuels are consumed in the presence of oxygen to generate energy.
Relative dating
This is used to put fossils in a chronological sequence. It provides evidence to determine which fossil is younger or older, depending on what layer it is found in. The specific age of the fossil cannot be determined.
Absolute dating
This allows us to determine the actual age of a fossil using elements that are present in the fossil.
