2A,B,C,D- structure and functions in living organisms Flashcards
what are the levels of organisation in organisms?
organelles, cells, tissues, organs, and systems
Organelles:a small, specialized structure within a cell that performs a specific function
Cell: The smallest unit of life, made of molecules
Tissue: A group of cells of the same type that work together
Organ: A structure made of one or more types of tissues that work together to perform a specific function
Organ system: A group of organs that work together to perform a specific function
Organism: An individual living thing that may be made up of one or more organ systems
what is the function of the nucleus?
NUCLEUS
* CONTAINS THE GENETIC MATERIAL (DNA) WHICH CONTROLS THE ACTIVITIES OF THE CELL
CYTOPLASM * AASEL-LIKE SUBSTANCE COMPOSED OF WATER AND DISSOLVED SOLUTES
* SUPPORTS INTERNAL CELL
STRUCTURES
* SITE OF MANY CHEMICAL REACTIONS, INCLUDING ANAEROBIC RESPIRATION
CELL MEMBRANE * HOLDS THE CELL TOGETHER, SEPARATING THE INSIDE OF THE CELL FROM THE OUTSIDE
* CONTROLS WHICH SUBSTANCE CAN
ENTER AND LEAVE THE CELL
what is the function of the cytoplasm?
CYTOPLASM
* A GEL-LIKE SUBSTANCE COMPOSED OF WATER AND DISSOLVED SOLUTES
* SUPPORTS INTERNAL CELL STRUCTURES
* SITE OF MANY CHEMICAL REACTIONS, INCLUDING ANAEROBIC RESPIRATION
what is the function of the cell mambrane?
CELL MEMBRANE
* HOLDS THE CELL TOGETHER, SEPARATING THE INSIDE OF THE CELL FROM THE OUTSIDE
* CONTROLS WHICH SUBSTANCE CAN ENTER AND LEAVE THE CELL
what is the function of the ribosomes?
ribosomes are found in the cytoplasm and the site of protein synthesis
what is the function of the mitochondria?
MITOCHONDRIA
* SITE OF MOST OF THE REACTIONS INVOLVED IN AEROBIC RESPIRATION, WHERE ENERGY IS RELEASED TO FUEL CELLULAR PROCESSES
* CELLS WITH HIGH RATES OF METABOLISM (CARRYING OUT MANY DIFFERENT CELL REACTIONS) HAS SIGNIFICANTLY HIGHER NUMBERS OF MITOCHONDRIA THAN CELLS WITH FEWER REACTIONS TAKING PLACE
what is the function of the cell wall?
CELL WALL
* MADE OF CELLULOSE (A POLYMER
OF GLUCOSE)
* GIVES THE CELL EXTRA SUPPORT, DEFINING ITS SHAPE
what is the function of the chloroplasts?
CHLOROPLASTS
* CONTAINS GREEN CHLOROPHYLL
PIGMENTS (TO ABSORB LIGHT ENERGY) AND THE ENZYMES NEEDED FOR PHOTOSYNTHESIS
what is the function of the vacuole?
- contains cell sap; a solution of sugars and salts dissolved in water
- used for storage of certain materials
- also helps support the shape of the cell
what does a plant cell have that an animal cell doesn’t
chloroplast, cell wall, vacuole
what are enzymes?
biological catalysts which speeds up a reaction without being used up itself (afterwards it is unchanged and free to catalyse more reactions). THEY CATALYSE METABOLIC REACTIONS
what are enzymes made up of?
proteins
how are enzymes made?
genes control the production of enzymes
why are enzymes needed?
because temperatures in organisms are low e.g., 37 degrees in humans, and without catalysts, most of the reactions that happen in cells would be far too slow to allow life to go on. Reactions can only take place quickly enough when enzymes are present to speed up the reaction
what is the difference between an extracellular enzyme and a normal enzyme (intracellular)
an extracellular enzyme (e.g., enzymes that are secreted in the intestine to break down food) functions outside the cell whereas an intracellular enzyme carries their function out within the cell
how do enzymes work? draw a diagram