Biology Year 11 Term 2 Phase 05

Module 2, syllabus dot points 2.2a, 2.2b, 2.2c, 2.3b, 2.2e, 2.3a, 2.3c

What is a heterotroph?

An organism that has to consume other organisms for food/nutrients.

What is an autotroph?

An organism that uses inorganic substances such as light, CO2, water, etc. to produce organic substances for their own food/nutrients.

What are examples of heterotophs?

Fungi, some protists, animals, most bacteria.

What are examples of autotrophs?

Plants, most protists, and some bacteria.

What processes do autotrophs use to produce their own food/nutrients?

Chemosynthesis and Photosynthesis

What are the two classifications of autotrophs?

Chemosynthetic and photosynthetic

What are examples of photosynthetic autotrophs?

Algae, plants, cyanobacteria.

What is an example of a chemosynthetic autotroph?

some bacteria, such as beggiatoa

What are the classifications of photosynthetic autotrophs?

Bryophytes, ferns, gymnosperms (conifers), angiosperms (flowering plants).

Out of the 4 classifications of photosynthetic autotrophs, which one has no vascular structure?

Bryophytes

How do bryophytes and ferns reproduce s*xually?

They produce spors

How do gymnosperms (conifers) reproduce s*xually?

They use the seeds in the cones that they drop.

How do angiosperms (flowering plants) reproduce s*xually?

They use their flowers and seeds within the fruit they produce.

What are examples of tissues/organs in plants?

Xylem, phloem, root, root hairs, meristem tissue

What is the function of the xylem in an autotroph?

To transport water from the roots to the leaves

What is the function of the phloem in an autotroph?

To transport sugar/glucose from the leaves to the rest of the plant.

What is the function of roots in an autotroph?

Gathers water and nutrients and supports plant/provides it with structure

What is the function of root hairs in an autotroph?

Increases the surface area to volume ratio to assist the absorption of water from the outside.

What is the function of the meristem tissue in an autotroph?

It is where the growth of the root occurs.

What is the structure/description of the structure of the meristem tissue?

Small bundle of cells that grow rapidly

What is the structure/description of the structure of the root hairs?

Very thin extensions

What is the structure/description of the structure of the root?

Wide web of branching roots

What is the structure/description of the structure of the phloem?

They have companion cells and sieve tubes.

What is the structure/description of the structure of the xylem?

Dense hollow tubes that are dead.

What are the different structures shown on a leaf cross-section?

Cuticle, epidermis, palisade mesophyll, vein, lower epidermis, spongy mesophyll, stomata.

What is the palisade mesophyll?

They contain high numbers of chloroplasts and it is where most photosynthesis occurs.

What are stomata (stoma singular)?

Pores that allow gases to move in and out of the cell.

What is the epidermis (lower and upper???)

Thin, transparent cells that allow loght to pass through to the other cells.

What is the vein/vascular bundle?

Thin tubes that transport water and nutrients around the plant. Contains xylem and phloem.

What is the waxy cuticle layer?

Thin, waxy layer that reduces water loss and provides protection.

What is the spongy mesophyll?

Loosely packed cells with lots of space around them for gases to move through them easier.

What are guard cells?

Cells that open and close the stomata to prevent water loss.

What is the main transport system within plants?

The vascular system.

What is the vascular system?

It connects every part of the plant, carrying water, glucose, and other dissolved substances around the plant to transport nutrients around.

What is the equivalent/similar thing to blood vessels in animals but instead in plants?

The xylem and phloem - they are a system of veins.

What is the difference between the xylem and phloem?

The xylem transports water, while the phloem transports other substances such as glucose.

Where do vascular bundles extend to?

From the roots, through the stems, to all the leaves, flowers, and fruits on a plant.

Which vascular bundle (xylem/phloem) is arranged on the outer side of the plant stem?

Phloem

Which vascular bundle (xylem/phloem) is arranged on the inner side of the plant stem?

Xylem

Why would the vascular bundles transport glucose to the root cells?

They do not receive sunlight, meaning they can not photosynthesise and therefore can not receive glucose another way.

What is the purpose of a root in a plant (in simple terms)?

To support the plant and obtain water and minerals from the soil.

Do the roots contain vascular bundles (xylem and phloem)?

Yes

What structures are found within a root structure?

Xylem, phloem (vascular bundles), root hairs, epidermis, meristem, root cap.

What does the meristem tissue do for the roots?

Allows high amounts of growth to take place and extends the roots further into the soil.

What are flowers (in simple terms)?

The reproductive (s*x) organs of a plant.

How can flowers relate to sperm and egg cells in humans?

Flowering plants need to fertilise their cells (pollen and ova) in order to reproduce.

What type of photosynthetic autotroph produces flowers?

Angiosperms.

What is an anther in a flower?

The structure that produces male gametes (essentially sperm)

What is a stigma in a flower?

Sticky part that extends above the flower to catch pollen

What is the sepal in a flower?

An outer layer of modified leaves which protect the flower before it opens.

What is the ovule in a flower?

The female gametes (essentially egg cells) contained within the ovary of the flower.

What is the petal of a flower?

Brightly coloured structures that attract pollinaters (bees, etc).

What is the filament of a flower?

The little stems that hold the anthers up high for pollinators to see.

What is the style in a flower?

A structure that holds the stigma above the flower and connects it to the ovary.

What is radioactive tracing?

Tracing the movement of radioisotopes within plants to determine if they are being converted into new materials.

How can the radioisotopes be detected during radioactive tracing?

A geiger counter

What are isotopes?

Isotopes of the same element which contain the same number of protons but different numbers of nuetrons (eg. carbon-12 has 6 neutrons, while carbon-14 as 8 neutrons)

What are radioactive isotopes?

Isotopes which are unstable (nucleus not holding up well) and emit heat and radiation.

What radioactive isotope was used/is typically used to map the path of carbon in photosynthesis?

Carbon-14

When an experiment is conducted on the track of carbon in the process of photosynthesis, would the geiger counter read high radioactivity in the leaves still the next day?

No it wouldn’t, as the radioactive carbon would move from the leaves to the fruit and further into the plant.

What structure allows for gas exchange in plants?

Stomata - controlled by guard cells.

What are the twom processes in plants that require gas exchange?

Photosynthesis and respiration

What gas exchange process occurs during the daylight?

Photosynthesis. Carbon dioxide moves into the leaves for photosynthesis, and the oxygen produced moves out.

What gas exchange process occurs during the night time?

Respiration. Oxygen moves into the leaves for respiration, and the carbon dioxide produced moves out.

What gas to stems and roots only require for cellular respiration?

Oxygen

How do stems exchange gases with the atmosphere?

Through small holes in the surface called lenticels

What are roots covered in that allows for efficient gas exchange?

Root hairs - maximise SA:V

Gas exchange in leaves: which structure in the leaf allows for efficient gas exchange in the leaf?

Spongy mesophyll

True or false: Gases dissolve into fluids in the plant to be transported around.

True.

How else can gas enter/exhcnage into a plant?

Via diffusion from the soil into the roots.

What are the walls/tubes in the phloem called?

Sieve tubes

What is the transpiration-cohesion-tension theory?

It is when water transpires - the water gets pulled on by a transpirational pull that crafts tension between the molecules. Due to the cohesion of the water molecules, they are all sticking to one another hence everything will be pulled up to transpire.

What is transpiration in simple terms?

Evaporation but for plants.

What is the transpiration step in the transpiration-cohesion-tension-theory?

When the stomata are open, water evaporates out of the leaves.

What is the cohesion step in the transpiration cohesion tension theory?

When water is pulled upwards, the water molcules hold onto each other and are pulled all together.

What is the tension step in the transpiration cohesion tension theory?

When the water evaporates from the leaves, this creates a negative pressure (pull) in the xylem (like sucking the top of a straw).

What is translocation?

The transport of glucose from where they are produced (sources) to where they are needed (sinks)

Where is glucose produced in a plant?

The leaf cells - otherwise known as companion cells.

How is glucose moved from the leaves to the phloem after photosynthesis and during translocation?

Active transport - requires energy.

What happens once there is a high concentration of glucose in the phloem cells during translocation?

Water is pulled into the phloem by osmosis

Where does the water come from that is pulled into the phloem during translocation?

Transpiration

Once there is a high concentration of glucose and water in the phloem cells, how is the glucose moved down to the sink (its destination) during translocation?

The pressure pushes the glucose to the next cell, and so on until it reaches the sink (roots, fruit, etc.).

What process then allows the glucose to move from the phloem to the sink during translocation?

Diffusion or active transport.

What direction does water travel in the xylem?

One way

What direction do nutrients travel in the phloem?

Both ways - meaning it requires active transport

How could you describe the movement of nutrients in the phloem?

From source to sink (leafs to fruits, etc).