Unit 1 topic 2: Multicellular organism Flashcards
Unicellular
- Singled-celled organisms consist of a single cell.
- Example: bacteria, protozoa and unicellular fungi.
Multicellular
- Community of cells that work cooperatively for the survival and reproduction of the organism.
- Example: Simple mosses, sponges and corals, plants and animals.
Specialised cell
- Cells that have a specific function.
- Have unique structural adaptations that enable them to carry out specific functions.
Organs
- Consists of two or more tissues that work together to perform one or more specialised tasks.
- Example: flowers, leaves and roots
Cell cycle
A cell cycle is a series of events that takes place in a cell as it grows and divides. … The cell then leaves interphase, undergoes mitosis, and completes its division.
Mitosis
Mitosis is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei.
Digestion
Breakdown of food into a form that can be used by an organism for metabolism
Chemical digestion
- Breaking apart complex molecules into simple molecules.
- Carried by enzymes (increase rate of food breakdown)
Absorption
- Most nutrient molecules produced through digestion pass through cell membrane by diffusion.
- Transported to circulatory system which transports to appropriate cells.
Assimilation
- Occurs in cells
- Monomers are built up into complex compounds
- Then converted into other forms as storage products for later use or broken down for energy release
Elimination
- Any undigested food is eliminated from gut as faeces = egestion
Movement of blood
- Moves through series of tubular vessels called arteries, veins and capillaries
- Heart moves blood through these vessels
structure and function of blood
Composed of red blood cells, white blood cells, plasma proteins and platelets – all suspended in a fluid called plasma.
Red blood cells (RBC)
. Transport oxygen from the respiratory surfaces to the tissues
. Packed full of red pigment called haemoglobin
The double circulatory system
. Called the double circulatory system because blood passes through the heart twice.
. Blood is moved around the body as a result of rhythmic contractions of the heart
Arteries
Blood vessels that carry blood away from the heart
Capillaries
Walls are composed of a single layer of thin flat cells and permeable to all blood components except RBC and plasma proteins
Veins
take blood towards the heart
Carriage of respiratory gases in the blood
. Oxygen
. Carbon dioxide
Lymphatic system
Network of tissues, vessels and organs that work together to move a colourless, watery fluid called lymph back into your circulatory system (your bloodstream).
Excretion
Animals process food into molecules needed by the body and for general life functions.
What is removed in Excretion?
Most metabolic waste is removed through surfaces in contact with the environment
What are the Excretory organs?
. Lungs/gills
. Kidney
. Skin
. Liver
Excretory organ: Lungs/gills waste product?
Carbon dioxide, water (cellular respiration).
Excretory organ: Kidney waste product?
Nitrogenous wastes (urea), water, inorganic salts.
Excretory organ: Skin waste product?
Water, inorganic salts, heat, small amounts of urea.
Excretory organ: Liver waste product?
Nitrogenous wastes (ammonia into urea) that is then excreted by the kidneys
Ammonia
. Highly toxic to animal cells
. Needs to be rapidly removed (fish through gills) or converted to a less toxic compound such as urea and uric acid (mammals and amphibians).
Urea
. Can be contained in body for limited period before removal.
. Energy is needed to convert ammonia to urea, but less water is needed for excretion.
Uric acid
. No water is needed for dilution but energy is also required to convert from ammonia
. Excreted as a thick white paste crystals in birds and solid pellets in insects
The Excretory system
. Includes a pair of kidneys that remove excretory products from blood plasma.
. The urine formed passes through the ureters to the bladder for storage and is eventually eliminated via the urethra.
Structure and function of the kidneys
. Bean shaped organ
. Composed of two layers of tissue: an outer, darker coloured cortex and an inner, lighter coloured medulla, surrounding a central cavity.
Structure and function of the kidney
. The renal artery (kidney) forms branches between the pyramids that deliver blood to the region containing nephrons
. Each kidney contains between one to two million nephrons.
Nephrons
. Consists of an elongated tubule
. One end has a group of blood capillaries via a cup-shaped Bowman’s capsule
. Down the other end is a collecting duct – which drains into the pelvis as urine and out through the ureter
The function of the kidney
. Removal of metabolic waste (excretion) and regulating water levels (osmoregulation).
.
Filtering
. Blood enters the capillaries under high pressure
.
What is Reabsorption?
. The process by which the nephron removes after and solutes from the tubular fluid and returns them to the circulating blood.
What is the Respiratory System?
Used for gas exchange in animals and plants
What is gas exchange?
Physical process in which the gass move passively by diffusion across a surface
What is Vascular tissue?
Complex conducting tissue, formed of more than one cell type, is found in vascular plants.
What is the main information about the leaf structure?
Stomata provide openings through the epidermis and cuticle- CO2 diffuses into mesophyll
Mesophyll
. Palisade mesophyll – densely packed with chloroplasts to maximise light absorption beneath the transparent epidermis
. Spongy mesophyll – irregular shape and contain chloroplasts. Air spaces allow gases to move through the leaf.
What is xylem?
Transports water, nutrients and minerals that were absorbed from soil via the root system
What are vessel elements?
straw like cells that are extremely efficient at moving water. Only found in flowering plants
What is a Tracheid cell?
Stack of empty cells that aren’t as efficient at moving water
The function of Phloem?
Transports sugars and other plant products
What is the function of the root system?
Absorb water and minerals from the soil
Support and anchor plant
Main energy storage area
What is a taproot?
Thick main root with side branches. Helps to reach water table and anchorage for large trees
What is a fibrous root
Many smaller roots. Grow quickly and provide a wide base.
What is the shoot system?
Water and dissolved minerals move to leaves through stem
