Unit 1 AOS 2 Flashcards
System Functions
Vascular Plants
Most multicellular plants, and have specialised conducting systems
Meristematic tissue
Type of plant tissue made of cells that can undergo cell division and continue dividing for the rest of the plants life
Permanent Tissue
Type pf plant tissue made of specialised cells that can’t divide
Vascular Plant Systems
2 conducting systems
- Above Ground Shoot System
- Below Ground Root System
Transportation systems in vascular plants
2 transport systems
- Xylem tissue
- Phloem tissue
Absorption of liquid in plants
- Water enters root cells via osmosis
- Water moves across cells the the cortex to xylem
Pathways of water and nutrient absorption in roots
2 pathways
- Extracellular Pathway
- Cytoplasmic pathway
Xylem tissue
Contains 2 types of water conducting cells, moves water from roots to the rest of plants, transpiration pulls water upwards
Types of water controlling cells
Tracheids and Vessels, both have thick cell walls, lose live contents, meaning they aren’t living
Extracellular pathway
Water diffuses into the roots in the gaps between the cells
Cytoplasmic pathways
Mineral ions are passively diffused into the cytoplasm of the next cell or are taken up by active transport in root hair cells
Transpiration
The passing out of unused water into the atmosphere. It occurs in leaves through air space in mesophyll tissue and is stomata
Guard cells
Guard stomata, when less water in the cell, stomata close, when more water, stomata opens
Stomata
Pores in epidermal tissues surrounded by 2 guard cells
Water movement in plants
Water is pulled upwards from transpiration and pressure in roots pushes it. Water column doesn’t break from adhesion and cohesion
Adhesion
Water creeps up plant cells by connecting to other substances eg. lignin
Cohesion
Water molecules staying together during movement
Translocation
Process of transporting sugars and inorganic materials
Phloem
Composed of sieve tubes and other cells, process of moving sugars and other organic material
Sieve tubes
No nucleus but is living, sieve cells form rows of elongated cells, forming sieve plates and perforated cell walls, companion tubes are closely associated
Tissues
Formed by cells of similar types or a single type acting to perform a specific function.
4 types of recognised tissue
- Epithelial
- Muscle
- Connective
- Nervous
Epithelial tissue
Covers internal and external surfaces
Muscle tissue
Contracts and enables movement
Connective tissue
Provides structure and support as well as energy and transportation
Nervous tissue
Made up of neurons, important for connectivity and control
Organ
Group of different types of tissues grouped together to form discrete systems that carry out specific functions
System
Group of organs that co-operate to carry out a specific function sustaining life
Mechanical digestion
Breaks food into smaller pieces but doesn’t alter the chemical formation
Chemical digestion
Breaks down food into simpler substances to be absorbed
Components of the digestive system
2 components
- Alimentary Canal
- Accessory Organs
Alimentary canal
The gastrointestinal tracht composed of organs that food moves through
Digestive system
Aimed to obtain nutrients from ingested food through either chemical or mechanical digestion
Accessory organs
Organs that release enzymes into the alimentary canal
Enzymes
Protein molecules that speed up chemical reactions and are sensitive to pH and temperature.
Types of enzymes
3 types
- Amylases
- Proteases
- Lipases
Lipases
Enzyme that breaks down fats and oils into fatty acids
Amylases
Enzyme that breaks down carbs into sugars
Proteases
Enzyme that breaks down proteins into amino acids
Gut flora
Bacteria and archaea in the large intestine
The mouth
Tongue and teeth responsible for mechanical digestion (chewing) and saliva mixes with food with amylase digesting starch.
Bolus
The product of chewed up food from the stomach that is ready to move down the oesophagus
The Oesophagus
A smooth tube that pushes bolus to stomach via peristaltic waves aka peristalsis.
The Stomach
Muscular organ that is surrounded in mucus, secretes hydrochloric acid and churns food, mixing bolus with pepsin resulting in chyme.
Pepsin
A protease that chemically digests protein. It has a pH of 1.5 which is quite acidic
Small Intestine
Surrounded in villi which are covered in microvilli that increase surface area for absorption. Intestinal juices with mucus and enzymes help digest and absorb chyme.
Parts of the small intestine
3 parts
- Duodenum (about 25cm long)
- Jejunum (about 2.5m long)
- Ileum (about 3m long)
The liver
An accessory organ that filters blood from the intestine, detoxifies chemicals, metabolises drugs, and secrets bile produced in the gall bladder to the duodenum.
The Gall Bladder
An accessory organ that concentrates bile
Bile
A yellow-green-brown substance that neutralises chyme as well as emulsifying lipids mechanically to increase their surface area to assist digestion.
The Pancreas
An accessory organ that secretes pancreatic juices that contain enzymes, bicarbonate ions to the duodenum to neutralise the pH of foods.
Large Intestine
Absorbs water and produces vitamins B and K as well as containing 700 species of bacteria and archaea
The Rectum and Anus
Stores remainder of waste material. When full the urge to defecate occurs via anus
