Module 2 - ORGANISATION OF LIVING THINGS Flashcards
what are colonial organisms
Colonial organisms are made up of a group of identical single-celled
organisms collectively called a colony. only one cell thick. example includes coral
describe unicellular cells
- a single cell is responsible for all of its own life processes
- always directly exposed to the external
environment.
-
describe multicellular cells
- Similar cells are grouped together
and perform specialised functions that combine together for the efficient functioning of the organism.
what is the division of labour
different cell types (tissues) are structurally suited to carry out different functions - increase effectiveness
What’s a young cell called?
embryonic
what does differentiate mean regarding cells?
- When cells become specialised to perform a particular function
- makes them structurally different from other types of cells and from the embryonic cells from which they arose.
what are stem cells and specialised cells?
- stem cells are undifferentiated, and are able to divide many times over a long period and become specialised.
- specialised cells are those cells with unique structures and functions in the body.
what is the difference between cell specialisation and differentiation?
Cell specialisation refers to the particular functions that a cell has. Differentiation is the process that a stem cell goes through to become specialised.
what is mitosis?
process of division, identical
copies of the original cell are produced. All cells in the organism, excluding the sex cells, contain the same genetic information in their genes.
what is a part of the plant that contains undifferentiated cells?
- the meristematic tissue, present in the young growing regions such as the root
and shoot tips - differentiated into specialised cells, such as phloem cells and xylem tissue, which the plant requires to function effectively
what is the process of embryo cell division?
zygote - blastocyst - gastrula
are specialised cells capable of surviving on their own?
no. They are reliant upon the other cells to carry out the functions that
they cannot. In order to function efficiently, there is a requirement for well-developed communication
and coordination between the many specialised cells.
how do animals relay messages around the body effectively?
chemical secretions and nerve cells
how do plants relay messages around the plant effectively?
In plant cells, communication is brought about by chemical and physical contact between cells because
there are no nerve cells and no centralised control centre.
how does the structure and specialisation of red blood cells prove how they are related to their function
- The function of red blood cells is to transport oxygen around the body in the
blood. - very small size and the biconcave shape of the red blood cell increase the SA:V,
- The absence of a nucleus or organelles in the cell allows more haemoglobin to be carried in the cell. The haemoglobin
contained within the red blood cell chemically binds with the oxygen in the lungs and releases it to the body cells.
what needs to happen in order for multicellular organisms to function effectively and live successfully
be a high level of organisation in the arrangement of these specialised cells.
what is the Hierarchical structural organisation
organelles, cells, tissues, organs, organ systems, organism
what are the four general types of tissues?
- epithelial tissue
- connective tissue
- nervous tissue
- muscle tissue
what is epithelial tissue?
- a tissue that covers body surfaces, protects organs and forms glands
- does not contain blood vessels and relies on the underlying connective tissue
for nutrients.
what are the two distinct surfaces on epithelial tissues?
- the surface that is exposed
to the exterior or the body cavity; - the other is the surface that is exposed to the adjacent tissue.
what is an example of epithelial tissue?
the skin
what is connective tissue?
tissue provides support, ensures that different parts of the body are bound together and protects against damage.
what is the matrix of connective tissue made out of?
made up of the protein fibres collagen (for strength) and elastin (for flexibility), and another substance to fill the spaces.
what are the types of connective tissue and their role?
fibrous connective tissue
loose connective tissue
adipose tissue - which consists of fat storage cells that function as energy storage, insulation and for
protection and cushioning.
cartilage - dense collagen fibres that provide not only strength but also
flexibility and cushioning.
what are nervous tissues?
highly specialised for their function of passing messages between themselves and other cells in the body.
describe the structure of neurons
- consist of multi-branched dendrites and an axon that extends out from the cell body.
what are muscle tissues?
contains muscle cells called muscle fibres that are highly specialised for contraction.
three types include skeletal, cardiac, and smooth.
what are the three organ systems in a plant?
- the shoot system > It supports the plant, enables the transport of substances around the plant, exchanges gases, and carries out photosynthesis and reproduction. eg leaves, stem
- the root system > plant below the ground. It is responsible for absorbing water and nutrients from the soil for the use of the rest of the plant. eg root hairs
- vascular system > system for transport. It is made up of xylem and phloem vessels.
what are the four types of tissues in plants?
- meristematic tissue
- dermal tissue
- vascular tissue
- ground tissue.
what is the meristematic tissue?
- found at the tips of roots and shoots
- cells divide to produce new growth.
- Cell differentiation to produce specialised cells can also take place
here.
what is the dermal tissue?
- protects the plant from damage and controls interactions with the plant’s surroundings.
- found on the outer layers of the stems, roots and leaves.
what is the epidermal layer?
- The epidermal layer is the outermost layer of the dermal tissue. It secretes a waxy layer called the cuticle, which is vital to reduce water loss from the plant.
- produce fine hairs on the surfaces of the leaves and stems. These hairs trap a layer of air next to the leaf, preventing
the flow of air and decreasing the evaporation of water from the leaf.
what is the vascular tissue in plants?
- responsible for the transport of substances around the plant
- found in the roots, stems and leaves.
- two main types > the xylem and the phloem.
- Xylem tissue transports water and mineral salts from the roots to the leaves.
- Phloem tissue transports the products of photosynthesis around the plant.
what is the ground tissue?
- all of the internal cells of a plant other than the vascular tissue
- tissue is the bulk of the
plant tissue and consists of a variety of different cell types that are specialised for food storage, support and photosynthesis.
what are heterotrophs?
Heterotrophs need to take in all of these nutrients from external sources.
what are autotrophs?
Autotrophs can produce their own organic nutrients and need to obtain water, mineral ions and the gases carbon dioxide and oxygen from external sources.
what is a vascular plant and a non-vascular plant?
- vascular plants possess a a transport system to move substances from one part of the plant to another.
- non-vascular plants do not possess a transport system and all nutrients are absorbed and wastes removed by diffusion and osmosis through the surfaces of the plant.
example of specific plant tissue functions?
transport of substances, photosynthesis, reproduction and gas exchange.
what is the xylem?
responsible for the transport of water, along with water-soluble nutrients and minerals, absorbed from the soil through the root system.
(letter after x is w - w for water)
what is the phloem?
conductive tissue composed of thin-walled cells that transport sugars in the form of dissolved sucrose, and other plant products from one part of a plant to another.
(‘Ph’ for food)
what are the two features that make up the shoot system?
stems - provides both structural support and a transport pathway between the roots and the leaves.
leaves - absorb sunlight and carbon dioxide and produce the organic compound glucose in the process of photosynthesis.
what are the types of tissue in the stem and what do they do?
– Dermal tissue is the outer layer of the stem.
– Vascular tissue consists of the xylem and phloem tissue organised in vascular bundles.
– Ground tissue is all the parts of the stem that are not dermal tissue or vascular tissue.
what is transpiration?
process by which water evaporates from the leaf
what cells are responsible for photosynthesis in mesophyll?
palisade cells - dense with chloroplasts and are the main photosynthetic cells
spongy cells - second main photosynthesis cell as have fewer chloroplasts
what are guard cells?
- control both the exchange of gases (such as carbon dioxide and oxygen) and the loss of water (as water vapour) through leaves.
- occur in pairs
- surround a stoma (stomata plural) (pore)
what is the main vein in leaves called?
- midrib (contains phloem and xylem tissue)
do plants carry out cellular respiration?
YES!! simply ‘masked’ or hidden by photosynthesis and so the observed exchange of gases by plants during the day differs from that at night.
how does plant cellular respiration occur?
- comes from the oxygen produced by photosynthesis
- any oxygen not used during cellular respiration is released by the plant to the outside environment.
- carbon dioxide released as a result of cellular respiration during the day is used as a reactant in photosynthesis.
What are some imaging technologies used to determine plant structure?
MRI, PET scans, NT scans, X-ray computed microtomography
where does most gaseous exchange happen in plants?
stomata and lenticels.
how does stomata work?
- opens and closes to let gas in and stop water etc coming out
- When the guard
cells fill with water and become turgid, the thin outer walls (which are more elastic) stretch outwards, but the thick inner walls (which are fairly inelastic) do not bulge, so they are pulled apart and the pore between them widens. When stomata lose water, the outer walls no longer bulge, so the inner walls move together again, closing the pore. - on leaves
how do lenticels work?
- exchange occurs in the woody parts of plants, such as the trunks and branches of trees and woody shrub
- relatively slow
-
what is the fish gaseous exchange system?
gaseous exchange via gills
- extracts the maximum amount of oxygen without water
- require water flowing over them, in one direction
how does gaseous exchange in insects happen?
Insects take in and expel
air through structures called spiracles, which are in effect breathing pores.
- have valves to regulate the opening and closing
- no lungs or capillaries so have tracheal system
digestion definition
the breaking down of large
and complex food particles into much
smaller and simpler particles. There
are two types of digestion: mechanical
and chemical. The overall aim of
digestion is to break down the particles
into substances that are small enough
to be absorbed through the intestinal
walls into the bloodstream.
pathway to the digestion system?
mouth, oesophagus, stomach, small intestine, liver, large intestine,
mouth digestion?
- mechanical breakdown of food by teeth
- chemical breakdown by Salivary amylase turning carbs into sugars
- tongue forms a mix of food and saliva into a ball of bolus
oesophagus digestion?
- epiglottis closes over trachea
- Food moves down the oesophagus through muscular contractions called peristalis.
- chemical digestion of starch continues to occur
stomach digestion?
- circular sphincter muscles control movement of what comes in and out of the stomach
- relaxation and contraction of the stomach walls continue mechanical digestion.
- bolus combined with gastric juices forms a mixture of chyme.
- remains here for 6 hours
small intestine digestion?
- enters the intestine through a small muscular opening, the pyloric sphincter
- pancreatic juices are released and continue the chemical breakdown of carbohydrates and lipids
- when lipids are present bile is also included which comes from the liver
- absorption of substances happens in the jejunum
what are the three main regions of the small intestine?
start - duodenum
middle - jejunum
end - ileum
what does the liver do?
- plays an important role in keeping sugars, glycogen and protein levels in balance in the body.
- It also detoxifies the blood
what are villi?
Villi are microscopic projections that are one cell thick on the wall of the jejunum. There are blood capillaries and lymph vessels in close contact with these cells. Small molecules diffuse or
are actively transported through the walls of the villi into the capillary or lymph vessels to be distributed throughout the body.
large intestine digestion?
- remaining undigested material moves to the large intestine.
- material is composed of substances such as water, salts and dietary fibre.
- two main sections - colon and rectum
what does the colon do?
water and some salts are absorbed back into the bloodstream, with the undigested material compacting into a more solid substance.
what does the rectum do?
remaining waste material, known as faeces, is moved into the rectum by peristalsis and then egested, or eliminated, from the body through the anus.
what is the transpiration-cohesion-tension theory?
This theory has at its core the evaporation of water from the leaves (transpiration) creating a suction pull of water up the stem from the roots.
- The cohesion of water molecules to each other - This forms a continuous stream of
water so that when molecules of water are drawn up the xylem other water molecules move with them. - Adhesive forces between the water molecules and the walls of the xylem vessel cause the water to rise up the sides. The narrower the vessel, the higher the water will rise up.
- Water is then drawn from the xylem tissue in the veins to replace the water lost from the mesophyll cells. This in turn increases the tension on the column of water in the xylem and draws
more water up from the roots.
what is the source-sink theory?
- movement of substances is caused by the formation of high- and low-pressure
regions within the phloem tissue. Movement occurs from the region of high pressure to the region of low pressure. The high-pressure region is in close proximity to where the sucrose is produced and is known as the source. The low-pressure region is where the sucrose is required and is known as the sink.
what is an open circulatory system?
-Invertetbraes → spiders, insects, crabs, snails, ect
- Involve one or more hearts and open-ended vessels
- Contraction of the heart pumps transport fluid ( hemolymph - mixture of blood and tissue fluid) into vessels near the head of the body that empty into large spaces called sinuses
- Nutrients and waste are exchanged via diffusion and the fluid is not sucked back into the circulatory system. Gas exchange does not occur here.
- Expansion of the heart causes haemolymph to return to it, entering visa tony holes called ostia.
- Disadvantage → not as efficient as closed systems because it has low pressure, hence fluid circulates slowly.
Transport fluid leaves the vessels, enters cavities in the body, and comes into direct contact with organs.
what is a closed circulatory system?
- All vertebrae and some invertebrates (worms)
- Transport nutrients and oxygen to all cells and carry, wastes away from cells.
The transport fluid is blood, which is contained in vessels at all times and never flows through body cavities. - Any chemical substances required by cells leave the capillaries in a dissolved form and move to the flood called interstitial fluid, which is the link between blood and the cells
- Advantages → pumps blood under high pressure, ensuring efficient transport. The 4-chambered heart is the most efficient as it separates oxygenated and deoxygenated blood.
- Pathway of blood: arteries → arterioles → capillaries → venules → veins → heart
compare heart structures of fish, amphibians, and mammals.
- Fish have a single circuit for blood flow and a two-chambered heart, 1 atria, and 1 ventricle.
- Amphibians have a 3 chambered heart, 2 atria and 1 ventricle
- Mammals have 1 chambered heart, 2 atria, 2 ventricles
what is the lymphatic system?
- The lymphatic system forms part of the transport system in mammals.
- The fluid that surrounds cells
diffuses out of the capillaries as they pass through the tissues (Fig. 6.11). To prevent this interstitial fluid from building up in the tissues, lymph vessels in the tissues absorb it. - fluid is known as lymph
what are platelets?
- are fragments of special
cells, also produced in the bone marrow. - have a function in the clotting of blood – they stick to each other and to the fibres that develop at the site of a wound when blood is exposed to air
- releases enzyme which sets steps to clot
arteries?
- Carry blood away from the heart - A for away
- Carry oxygenated blood, except when moving blood from the heart to the lungs (pulmonary artery)
Arteries have:
- High pressure fast moving blood → pumped out in regular bursts
- Thick elastic vessel walls → withstand pressure and elasticity allowing for contractions and expansions
-No valves as pressure is too strong
Smaller lumen
veins?
Return blood towards the heart → vein moves blood into the heart
Carry deoxygenated blood except when moving blood from lungs to heart (pulmonary veins)
Veins have
Low pressure and slower moving blood → Pressure decreases away from the heart
Thinner vessel walls
Fewer elastic fibres → do not need to stretch and recoil
Have valves → prevents backward flow
Much larger lumen → allows for easy blood flow
what are the mechanisms of veins to prevent backflow?
Contraction of muscle tissue → muscles around veins contract, walls become compressed, propelling blood towards the heart.
Valves at regular intervals → like one-way swing doors, the pressure of blood trying to flow backwards closes the valve’s ‘door’.
Capillaries?
- Connect arteries to veins
- Super tiny vessels that bring blood into close proximity to the tissues → enable gas exchange between blood and body cells
- Carry both oxygenated and deoxygenated blood
- Thin structure → diffusion for substance exchange (slow and passive process), also suited to the slowing of blood flow
- Form expansive network → spread blood flow over the large surface so no cells are far from the blood supply.
Maximising exchange
Thin walls → 1 cell thick, to not travel far
Small diameter → lumen only 1 blood cell thick, forces single file and slowing flow.
what is systematic circulation?
The pumping of oxygenated blood to all parts of the body and the return of deoxygenated blood to
the heart
what is pulmonary circulation?
The pathway of blood from the heart to the lungs and back to the
heart
what are some examples of change in composition of the transport medium?
- as blood passes through all organs (except lungs) concentration of oxygen decreases and carbon dioxide increases
- An increase in digestive end products (glucose and amino acids) is seen in blood that has passed through an organ involved in absorbing digested food, such as the small intestine.
- Glucose may be added or removed.
-Urea is added to the blood when proteins are broken down and nitrogen removed.
- Toxins and substances such as alcohol are removed from the blood.
-Some vitamins and iron are removed.
