AOS2 Flashcards
Plant cells; Vascular tissue.
Transports water and minerals throughout the plant.
2 major plant cells:
Xylem cells: Transports water and minerals from the roots to the leaves of the plant.
Phloem cells: Transports sugars and nutrients throughout the plant.
2 plant systems.
Root System: Absorbs water and nutrients from the soil and provides the plant with support and structure.
Shoot System: Reproductive, flowers and Non-reproductive, roots.
Dermal tissue.
A single layer of cells covers the outside of a plant.
It forms a physical barrier between the plant and the environment; reducing water loss and physical damage.
Ground tissue.
carries out metabolic functions.
Plant vascular systems: Pathways
Extracellular pathways: roots absorb the majority of water from the soil.
Cytoplasmic pathways: roots absorb most nutrients and essential minerals from the soil.
Transpiration.
Evaporation of water from leaves and movement of liquids up the xylem (water drawn up from the xylem).
water evaporates from the leaf and exits through the stomata.
Translocation.
Movement of substances from a source to other tissues in the plant via the phloem.
Stomata.
Small pores on the leaf’s surface that open and close to regulate gas exchange.
Digestive system.
Breaks down foods into smaller molecules, to be absorbed by small intestine and transported to cells around the body.
2 types of digestion.
Physical digestion
–> Breakdown of food into smaller pieces by chewing.
Chemical digestion
–> Breakdown of food into smaller molecules by digestive enzymes.
Excretory system.
Removes excess and unwanted substances from the body and maintains the ideal concentration of water and solutes.
Endocrine system.
Hormones are produced and released and transported all over the body via the bloodstream.
Homeostasis.
Maintenance of a relatively stable internal environment in the body despite the changes in the external environment.
Role of hormones in homeostasis.
Control of blood glucose levels and control of blood pressure.
Negative feedback
The effectors’ response counteracts the stimulus that was detected by a receptor.
High Blood glucose.
High Glucose (stimulus) –> Beta cells (receptor) –> Insulin (information relayed) —> Muscle(effector)–? glucose absorbed (response) —> homeostasis.
Low Blood glucose.
Low Glucose (stimulus) –> alpha cells (receptor) –> Glucagon (information relayed) —> Muscle-liver(effector)–> glucose- from glycogen released into the bloodstream (response) —> homeostasis.
High water
High water (stimulus) –> hypothalamus-Osmoreceptors (receptor) –> Less ADH (information relayed) —> Kidney(effector)–> absorbs less water, water goes out in the urine. (response) —> homeostasis.
Low water
Low water (stimulus) –> hypothalamus-Osmoreceptors (receptor) –> More ADH (information relayed) —> Kidney(effector)–> reabsorbs water from the kidney. (response) —> homeostasis.
Glucagon
a hormone secreted by alpha cells of the pancreas when blood glucose levels are low
Insulin
a hormone secreted by beta cells of the pancreas when blood glucose levels are high
Glycogen
Stored Glucose
Pancreas
Releases insulin and Glucagon that controls blood glucose.
Liver
Takes up glucose when levels are high and releases glucose when levels are low.
Stores glucose –> Glycogen
Muscles
Take up and store glucose when insulin is present.
Fat cells
Take up glucose when insulin is present. Uses glucose to make more fat.
Brain.
Takes up glucose when it needs energy and doesn’t require insulin.
