Module 2 Flashcards
Level of organisation in organisms
Organelles cells tissues organs systems organisms
Unicellular organisms
- Contain only one cell responsible for all life processes
- Simple structure
- Limits metabolic reactions
- Large surface area for all substances to diffuse across
Colonial organism
- Cells that form a cooperative group (colony) but can survive on their own
- Could be classed as a single celled organism
- More efficient as a colony
- EXAMPLE: Blue-bottle
Multicellular organism
- Made up of different types of cells
- Similar cells grouped together that communicate to perform specialised functions that combine together for efficient functioning
- Rely less on diffusion and are less efficient
- All cells have the same DNA
- Could not survive by themselves
- EXAMPLE: Animals and Plants
Cell differentiation
less specialised cell changes to become a specialised to carry out specific functions. This makes them more efficient.
Cell specialisation
specific function which a cell has, determined by their physiology and cellular structures. They develop suitable structural features which allow them to carry out their functions and this makes them structurally different from other types of cells.
Skeletal muscle
long and have striation which are caused by the arrangement of the actin and myosin in them. They are attached to the bones and they cause movement.
Cardiac muscle
fibres are present in the heart and also have striations, the individual cells have connection junctions that are necessary or the coordinated beating of the heart.
Smooth muscle
do not have striation and their contractions push substances through specialised organs such as the gastrointestinal tract, the blood vessels and the urethra which leads from the bladder.
Fish respiration
- Water enters the fish
- Water is pumped through gills
- Oxygen diffuses in and out of capillaries
- Water exits the fish
Insect respiration
- Use trachea for gas exchange
- Instead of lungs, insects breathe with a network of tiny tubes called tracheae. Air enters the tubes spiracles and the air then diffuses down the tracheae
Reptile respiration
- Gas exchange in alveoli
- When its mouth is full of air, the reptile will push the air down into the lungs.
- The nostrils are then closed and the floor of mouth is raised, forcing the air into the lungs for gas exchange.
4 plant organs
roots, leaves, stem, flower
Function of nasal cavity
the sticky mucous membrane lining the nasal cavity traps dust particles, and tiny hairs called cilia help move them to the nose to be sneezed or blown out.
Function of nose
air is inhaled into the body through the nose
Function of pharynx
enables you to swallow and is a pathway for food
Function of tongue
vital for chewing and swallowing food
Function of larynx
voicebox which helps you speak
function of trachea
windpipe which provides air to and from the lungs
function of lungs
conducts gas exchange for respiration
function of bronchi
shuttle air to and from the lungs – highways for gas exchange.
function of bronchioles
ensure that incoming air is supplied to the alveoli
function of alveoli
exchange oxygen to carbon dioxide in the bloodstream
What is the diaphragm
thoracic muscle that lays beneath the lungs and aids in inhalation/exhalation
function of nervous system
To coordinate bodily function by passing electrochemical signals, to detect and respond to external stimuli
Organs in nervous system
Brain, sensory organs (eyes, ears, tongue, skin), nerves
Function of digestive system
To breakdown and absorb food
organs in digestive system
Stomach, intestines, mouth, liver
Excretory system function
To rid the body of metabolic wastes
Excretory system organs
Kidney, bladder, urethra, ureters
Cellular respiration in plants
Break down sugar and turn it into energy - mitochondria
Photosynthesis in plants
Harness energy from sunlight and turn it into chemical energy - chloroplast
What is the stomata
• Tiny pores that cover epidermis • Gas enters and leaves • Each has a pair of guard cells - Open and close throughout day - Have chloroplast - Reduce water loss
Heterotrophs
Organisms that feed on others because they cannot provide their own energy supply
Autotrophs
Organisms that can make their own energy and do not depend on others.
5 steps of nutrition in heterotrophs
- Ingestion – intake of food (eating)
- Digestion – breakdown of food into soluble molecules that can be easily absorbed
- Absorption – basic units of food absorbed into the bloodstream
- Assimilation – turning the ‘food’ into tissue
- Egestion – elimination of wastes
Mechanical digestion
(Physical) – chewing, churning, moving
Involves physically breaking the food into smaller pieces.
Chemical digestion
(Enzymes) - Break down large complex molecules into simpler molecules
Xylem Structure
Lignin provides strength to stop the vessels from collapsing.
Tracheids transport water and are elongated with end walls that taper to a point and also impregnated with lignin
Fibres are also elongated and lignified, providing support to the xylem tissue.
Phloem Structure
Phloem – sugar transport tissue in plants
Sieve tub elements – living cells without cytoplasm and mitochondria but without other organelles
Sieve plates – the perforated transverse walls of the sieve elements which allow sap to flow from one element to the next
Companion cells – associated with each sieve element and they are responsible for keeping them alive
Cohesion/ Adhesion
The ability of water molecules to stick to other water molecules due to high intermolecular forces
Transpiration
Loss of water from plants by evaporation of water vapour through the stoma of plant leaves.
Negative pressure
When an area of lower pressure than the other surrounding it. Creates a ‘pulling’ force
Translocation
Source – Place that produces or stores sugar (leaves and roots)
Sink – Place in need of sugar
Function of waxy cuticle in plants
A thin protective outer covering. Protects against water loss.
Function of Upper/Lower epidermis in plants
Aid structural support and allow light to pass through.
Function of Palisade mesophyll
Primary site for photosynthesis.
Function of Spongy mesophyll
Allow gases to diffuse through secondary site for photosynthesis.
Function of Vascular tissue: Xylem cells
Transport water + nutrients upwards from the roots to the rest of the plant.
Function of Vascular tissue: Phloem cells
Conduct food from leaves to rest of the plant
Function of Guard cells
Cells close the stomata in response to environmental conditions.
Function of Stomata
Allow gases to enter and exit. Holes allow loss of water vapour
Function of RBC
Transport oxygen, carbon dioxide and haemoglobin
Function of WBC
Transports antibody into the plasma to fight pathogens
Function of platelets
Clumps blood to control bleeding
Function of plasma
Carries nutrients (glucose, amino acids, proteins, ion, waste products and small amounts of carbon dioxide
Function of veins
Veins return blood to the heart and have thinner walls than those of the arteries.
function of arteries
Arteries carry blood away from the heart with a strong structure that is able to withstand the high pressure in which the blood is moving
Function of capillaries
Transfer oxygen and nutrients through blood.
Open circulation
- Fluid is not combined to vessels
- Circulation is slow
- Transports nutrients not oxygen
- Found in arthropods e.g. insects and mollusc
Closed circulation
- Blood moves through the body enclosed in a network of tubes of different sizes that lead to and away from the heart
- Blood circulation is rapid
- Nutrients, wastes and gases are carried by blood
- Found in larger, active animals e.g. mammals, amphibians, birds and fish
