module 2 Flashcards
cellular respiration
- mitochondria
- glucose + oxygen → carbon dioxide + water + energy (ATP)
photosynthesis
chloroplasts
carbon dioxide + water → (in the presence of sunlight) oxygen + glucose
what do autotrophs need
carbon dioxide
- produce food themselves
what do heterotrophs need
oxygen for cellular respiration
root system
- absorbs water and nutrients for plant growth
types of roots
tap root and fibrous
root hairs
increases surface area for absorption
fine like hari structures
root nodules
- found on legumes
-Home for nitrogen fixing bacteria → found places with low nitrogen
root tip
- Protective cover for the root
Specialised cells → statocytes (enable plant to detect gravity → dense organelles that sink to the bottom and indicate which way gravity is pulling)
function of the stem
Support for leaves, flowers and fruits
Transport of fluids between root and leaves
Storage of nutrients
Production of new living tissue
vascular bundle
bundle made up of fluid and nutrient transport tissue –> xylem and phloem
xylem
- mineral ions and water
- dead cells arranged to produce a continuous hollow tube
walls strengthened with lignin - unidirectional
- occurs at root hairs –> moves up the stem –> photosynthesis in the leaves –> the rest exits through the stomata
- transpiration pull brings it up
TACT
- transpiration adhesion cohesion tension model
- explains the movement of water and dissolved mineral ions in plants
1. water and ions diffuse through the soil into root hairs
2. water moves up the stem due to the transpiration pull
mechanisms that support: - capillary action –> narrowness of xylem tubes
- cohesion –> hydrogen bonding of water molecules
- adhesion –> attraction between water molecules and the xylem wall
- potometer
transpirational pull
a force caused by water draining out of the stomata and needing tto replace water in the leaves
phloem
- Transports dissolved nutrients and sugars
- sieve tubes and plates
- companion cells
- bidirectional
sieve tubes
series of joined end to end with sieve plates –> transports sugars
companion cells
actively transports sugars in and out of the phloem
- has a nucleus
- Unloading and unloading of nutrients in and out of of the sieve elements
- pressure flow hypothesis
Pressure flow hypothesis:
- Process responsible for the movement of sugar through the phloem
- Allows dissolved nutrients and sugars to be translocated from the source (site of sugar production) to the sink (site of sugar removal/use)
- Energy comes from companion cells
- glucose is converted into sucrose
- sucrose is loaded into the sieve tubes
- water follows the sucrose and moves into the phloem tissue by osmosis
- due to the low concentration of water in phloem active transport - high water pressure at the source forces the phloem sap to move towards the sink –> roots –> moves from one sieve cell to another
- after it reaches the root the sucrose is unloaded into the root svia active transport
- water returns to the xylem due to high concentration in phloem and not xylem
external leaf structure
- petiole
- veins
- leaf blade
internal leaf structure
- upper epidermis
- palisade mesophyll
- spongy mesophyll
- lower epidermis
palisade mesophyll
Contains chloroplasts and elongated in shape
Photosynthesises and contains chlorophyll
Closer to the upper epidermis as it can catch more sunlight which increases the rate of photosynthesis
spongy mesophyll
Contains chloroplasts but not as much
Loosely packed and large air spaces around them
Oxygen and carbon dioxide can easily diffuse through
upper and lower epidermis
Tightly packed layer of cells
Reduces water loss
Has stomata
gas exchange in plants
simple: moss and alge
larger –> specialised gas exchange system
- oxygen leaves through mesophyll
- water vapours leave through xylem
and stomata
- lenti
stomata
microscopic opening the cells pores
rate of transpiration
Humidity → reduces transpiration rate
Temperature → water loss is higher until the maximum is reached → plateaus
Wind velocity → increases transpiration rates
photosynthesis
traced through aphids or ring barking
- traced through radiotopes (carbon 14 and oxygen 18)
trace the movement through the phloem
- light dependent –> atp and nadph
-light independent –> occurs in the absence of light
Circulatory/cardiovascular system
Transports substances around the body and transports wastes out
- Heart, blood vessels (veins, capillaries, arteries)
Respiratory system
Allows for gas exchange
Breathing (CO2 out, O2 in)
Lungs trachea, pharynx, larynx, bronchus, alveoli, diaphragm
Digestive system
Digests food and absorbs nutrients that are to be used on other body cells
- Mouth
Pharynx
Oesophagus
Stomach
Small intestine
Large intestine
vertebrate herbivore
- red kangaroo
Grass diet → fibrous and high in cellulose but low in proteins and carbohydrates
Sharp incisors and molars that move to the front in order to consume the low quality food and break down the cellulose in leaves
Long and complex digestive tract with caecum to absorb and break down nutrients
Foregut fermenters → contain bacteria and fungi that help break down the organic matter (symbiotic relationship)
vertebrate carnivore
tiger quoll
Meat → easily broken down
Short and simple digestive tracts and no caecum
Sharp canines, premolars and incisors
mouth
- chemically and mechanically breaks down food
Mechanically - Teeth bite chew and grind to break down food and increase the surface area for the action of digestive enzymes
Chemically - Digestive enzymes
Amylase → breaks down starch
Lipase → breaks down fats
Tongue mixed food with saliva → bolus that moves down the oesophagus into the stomach –> bolus
amylase
breaks down starch
lipase
breaks down fat
stomach
bolus is moved to the stomach form the mouth
- chemical: Stomach contains HCl
HCL activates pepsin → enzyme that helps chemically break down proteases (protein)
- mechanical: contractions
Helps breakdown fine particles that increases the surface area of food particles in contact with pepsin
pepsin
enzyme that helps chemically break down proteases
small intestine
The partially digested food passes the pyloric sphincter → into the small intestine
Duodenum → receives secretions from the gallbladder and the pancreas
Sugars and amino acids are absorbed into the capillaries by diffusion and active transport
Villi on the surface which increases surface area
large intestine
Unabsorbed food from the small intestine moves to the large intestine
Caecum and colon
Caecum: important for herbivores to break down cellulose
Colon: helps absorb water and nutrients
rectum and anus
- waste products move from large intestine to rectum
- stores the faeces until it can be eliminate through the anus through defection
Gaseous exchange
→ the biological process through which gases are transferred across cell membranes to either enter or leave the blood
gas exchange surfaces
- Moist so gases can easily dissolve and cross the membrane
- Thin so gas can easily diffuse into the bloodstream
- Have a rich blood supply so that diffused gases can be rapidly transported around the body
- Large surface area to maximise diffusion
insects
- open circulatory system
- gas exchange through spiracles and tracheae
mammals
- mouth nose pharynx trachea bronchi bronchioles alveoli
alveoli
small sac like structures that are the primary structures used for gas exchange in the mammalian respiratory system
- surrounded by capillaries
- Oxygen diffuses across its membrane into capillaries which enter the blood cells that create oxygenated blood
- Carbon dioxide from capillaries diffuse through to the alveoli and exit the body
Increases surface area
circulatory system
Rapidly transport nutrients and remove metabolic wastes
open cs
Open → circulating fluid bathes the internal organs directly
Heart pumps blood through the blood vessel that carries the blood (haemolymph) towards organs and tissues → blood leaves these blood vessels → goes to tissue → goes back to the heart through tiny pores in the heart called ostia
close cs
Closed → circulating fluid is contained within a system of vessels
heart and blood vessel (c a v)
simple tube heart
Heart moves haemolymph through open ended vessels
Heart is divided into chambers separated by valves to ensure the one way flow of haemolymph → (ostia)
After the exchange has taken place the hemolymph is carried back to the heart
four chambered heart
birds and mammals
- double circulatory
pulmonary
systemic
pulmonary
heart to lungs and back –> oxygen and carbon dioxide is exchanged
- right atrium to right ventricle
- gas exchange occurs in the alveoli
- oxygenated blood returns to the left atrium of the heart via the pulmonary vein
systemic
heart body and back
left atrium and left ventricle
blood vessels
arteries capillaries veins
arteries
- Carry blood away from the heart → oxygenated
- Pulmonary artery is the only exception → carries deoxygenated blood away from the heart
- Delivered to cells to undergo cellular respiration
- Thick muscular walls containing elastic fibres
- Allows for high pressure and can expand
- Small diameter to maintain pressure flow
capillaries
- Microscopic vessels that allow for the exchange of nutrients and wastes
Between tissues and blood - Tiny vessels that link arteries and veins
- Blood goes from oxygenated to deoxygenated as it goes through the capillary beds
- One cell thick in order to increase efficiency of gas exchange and nutrient exchange
- Also slows down the flow
veins
- Carry blood back towards the heart → deoxygenated
- Only exception → pulmonary vein
Carries oxygenated blood back towards the heart and the lungs - Needs to go to the lungs in order to be oxygenated and to get rid of the carbon dioxide
- Thin muscular walls with little elastic fibre
- Blood is low in pressure after it reaches the veins
- Flexible walls → allows blood to be pushed along by contractions in skeletal and bodily muscles
- Large diameter as high pressure is not needed → heart doesn’t need a rapid delivery of blood to tissues
- Contain internal valves → prevent blood flow
red blood cells
erythrocytes
- Biconcave disc shape
- Smaller than white blood cells → 7 - 8µm
- Produced in bone marrow
- Contains 270 million specialised iron rich protein molecule → haemoglobin
white blood cells
- Leukocytes
- Fight infection by foreign pathogens →bacteria and viruses
- Have a nucleus
- 8 - 20µm
platelets
- Thrombocytes
- Small irregularly shaped fragments
- 5 -9 days
- Released thread like fibres →forms blood clots
