Module 2: Organisation of Cells Flashcards
What are unicellular organisms?
Single celled organisms either eukaryotic or prokaryotic which are responsible for all its own processes
What are colonial organisms?
Identical cells working together which may contain cells with specific rolls
What are multicellular organisms?
Organisms made up of many different cells and have specialised cells which can not live independently
What are tissues?
Cells in multicellular organisms that have been organised into groups
What are specialised cells?
Cells which differentiate from stem cells to perform a certain roll. Once stem cells have been specialised they can no longer differentiate
What are the two types of stem cells?
Embryonic stem cells and adult stem cells from bone marrow
How does structure impact the roll of specialised cells?
Cells may be flattened, elongated or exposed edges may be extended into folds to create a higher SA:V
What is a transport system?
A system of vessels in which substances are transported
What are the vascular tissues in plants?
Roots, stem, leaves and stalks
What is xylem?
One of the two types of transport tissue in vascular plants
What is xylems basic function?
To transport water and nutrients from roots to stems and leaves
What are the two main types of elements in xylem?
Xylem tracheids
Xylem vessels
What are the walls of xylems reinforced with and why is it important?
They are reinforced with lignin thickenings laid down in rings which prevents the vessels from collapsing
What is the transpiration stream?
The way water moves against gravity in the xylem
How does the transpiration stream work?
As water evaporates through the stomata it creates a concentration gradient, creating a suction pull on the water
What is the main function of roots?
To anchor the plant and absorb water and inorganic nutrients from the soil
What is the epidermis of the root?
It is the outermost layer of the root
What are the four main types of tissue in animals?
Epithelial, connective, nervous and muscle tissue
What is epithelial tissue?
A covering that lines body surfaces and cavities and protects organs
What is connective tissue?
Tissue which provides support and holds various parts of the body together
What is collagen?
The main structural protein in connective tissue
What is elastin?
Protein which contributes to the elasticity of the skin
What are the three types of connective tissue?
Fibrous, loose and adipose tissue
What is the nervous tissue comprised of?
The brain, spinal cord and peripheral nerves
What are neurons made of?
Dendrites and an axon
What is muscle tissue?
Tissue composed of muscle cell called muscle fibre
What are the three types of muscle cells?
Skeletal, cardiac and smooth
What are skeletal cells?
Long fibres with striations that are attached to bones and cause voluntary contractions
What are cardiac cells?
Cells in the heart that have striations and cause involuntary movement
What are smooth cells?
Cells in organs that use contractions to push substances and do not have striations
What are the four main types of tissue found in plants?
Meristematic, dermal, vascular and ground tissue
What is meristematic tissue?
Tissue made from undifferentiated cells found in the tips of roots
What is dermal tissue?
Tissue which secrets a cuticle which reduces water loss
What is ground tissue?
All the internal cells of plants other than vascular tissue
How does water move into roots?
By the process of osmosis
How do minerals move into roots?
Through diffusion
What is transpriation?
Evaporation of water from leaves
What are mesophyll?
Cells responsible for photosynthesis in the middle layer
What are palisade cells?
Types of mesophyll, located below the upper epidermal
What are spongy cells?
Cells which are loosely packed for gases to move
What controls the exchange of gases and water in plants?
Guard cells
What are guard cells?
Bean shaped cells that open and close a stoma
How can MRI be used to understand plants better?
To create 3D images which can be studied more closely
How can the movement of products in plants be traced?
Using radioactive tracer carbon 14
How do stoma open?
Guard cells undergo photosynthesise which increases the concentration of glucose. Water enters the guard cell through osmosis causing it to become taught therefore opening the stoma
How do stoma close?
At night less glucose is produced in the guard cell and water leaves them closing the stoma
What are lenticels?
Pores on woody parts of plants where gas exchange can occur
What happens if there is too much carbon dioxide in organisms?
It becomes too acidic interfering with enzymes
What are the four characteristics of gaseous exchange sites?
- Large surface area
- Moist thin surface for gas to diffuse through
- Close proximity to an efficient transport system
- Have greater concentration on one side of the membrane than the other
What are alveoli?
Air sacs in lungs which oxygen and carbon dioxide are exchanged between the blood and air
How does respiration occur in fish?
Water enters through the mouth and passes through the gills which have gill filaments to increase the surface area
What is the countercurrent exchange?
It is the way fish absorb oxygen more efficiently. Oxygen rich blood is exposed to water with high levels of oxygen and oxygen poor blood is exposed to water with lower levels of oxygen.
How does gas exchange occur in insects?
They take in and expel air through structures called spiracles and they do not have lungs
What are heterotrophs?
Organisms that need to take in all their nutrients
What are autotrophs?
Self feeding organisms, producing its own nutrition
What is the enzyme released in the mouth and what does it help breakdown?
Amylase is released and starts the breakdown of carbohydrates
What is a bolus?
A small ball of food which can be swallowed
How does food move from the mouth to the stomach?
It moves down the oesophagus by the muscle contractions called peristalsis
What is broken down in the stomach?
Proteins
What is the duodenum?
The first half of the small intestine where proteins, carbohydrates and lipids are broken down
What is the jejunum?
The second half of the small intestine where absorption occurs
What are absorbed into the body via the villi?
Amino acids, glucose, fatty acids and glycerol
What are villi?
Small projection in the small intestine which increases the surface area for absorption
What is the lacteal?
It is in the centre of the villi which connects to the lymph system
What is absorbed into the blood system?
Glucose and amino acids
What is absorbed into the lymph system?
Fatty acids and glycerol
What are the two main purposes of the liver?
Keeps sugars, glycogen and protein levels balanced and detoxifies the blood
What are the two main parts of the large intestine?
Colon and rectum
What happens in the colon?
Water and salts are absorbed
What happens in the rectum?
Faeces are stored
What is cohesion?
Water molecules sticking together creating a continuous stream
What is adhesion?
Adhesive forces between water molecules which force water to rise up in tubes
What are the types of phloem cells?
Sieve tube cells and companion cells
What do sieve tubes cells do?
They form channels allowing sugars to flow through
What is translocation?
The movement of sugar in plants
What is the source (source sink theory)?
The high pressure area where sucrose is produced
What is the sink (source sink theory)?
The low pressure area where sucrose is needed
What is the lacteal?
It is in the centre of the villi which connects to the lymph system
What is absorbed into the blood system in the small intestine?
Glucose and amino acids
What is absorbed into the lymph system?
Fatty acids and glycerol
What are the two main purposes of the liver?
Keeps sugars, glycogen and protein levels balanced and detoxifies the blood
What are the two main parts of the large intestine?
Colon and rectum
What happens in the colon?
Water and salts are absorbed
What happens in the rectum?
Faeces are stored
What is cohesion?
Water molecules sticking together creating a continuous stream
What is adhesion?
Adhesive forces between water molecules which force water to rise up in tubes
What are the types of phloem cells?
Sieve tube cells and companion cells
What do sieve tubes cells do?
They form channels allowing sugars to flow through
What is translocation?
The movement of sugar in plants
What percentage of blood is made from red blood cells?
41%
What is the sink (source sink theory)?
The low pressure area where sucrose is needed
What is an open circulatory system?
- Open ended blood vessels
- Blood is pumped into cavities around organs
- Exchanges only nutrients and wastes
What are open circulatory systems most commonly found in?
Invertebrates
What is the transport fluid usually called in open circulatory systems?
Haemolymph
What is a closed circulatory system?
- Made up from blood vessels and a heart
- Sealed system
Transports nutrients, oxygen and carries wastes away from cells
What are closed circulatory systems most commonly found in?
Vertebrates
What are closed circulatory systems known as?
Cardiovascular system
What are veins?
Vessels with thin walls which carry deoxygenated blood from organs to the heart
What are arteries?
Vessels with thick elastic walls which carry oxygenated blood from the heart to organs
What are capillaries?
Tiny blood vessels that have a wall only one cell tick
What is the function of the lymph system?
To absorb interstitial fluid in tissues and plays an important role in the immune system of the body
What does blood carry?
Heat, nutrients, gases and excreted wastes
What percentage of blood is made from plasma?
55%
What percentage of blood is made from white blood cells and platelets?
4%
What is a red blood cell?
Is a cell which is produced in bone marrow and does not have a nucleus and contains haemoglobin which is an oxygen carrying protein
What is a white blood cell?
Is a cell larger than RBC that is produced in bone marrow and functions as a part of the immune system
What are platelets?
They are fragments of specialised cells produced in the bone marrow which clot blood when it is exposed to air
What is plasma?
It carries RBC, WBC, plasma proteins, nutrients, gases, wastes, ion, hormones and vitamins and consist of about 90% water and 10% protein
What are the top chambers in the heart?
Left and right atria
What are the bottom chambers in the heart?
Left and right ventricle
What vessel does deoxygenated blood enter and which atrium?
It enters into the right atrium via the superior and inferior vena cava
What vessel transports blood to the lungs?
The pulmonary artery
What vessel does oxygenated blood enter and which atrium?
It enters into the left atrium via the pulmonary vein
What is systemic circulation?
Is the movement of blood from the heart to lungs
What is pulmonary circulation?
Is the movement of blood from the heart to the body
