TOpic 8

What are autotrophs?

Organisms that produce their own energy sources

What is the other name for autotrophs?

Primary producers

What are heterotrophs?

Organisms that obtain most nutrients from other organisms

What is another name for heterotrophs?

Consumers and/or decomposers

What are some sources of nutrients for heterotrophs?

Autotrophic and heterotrophic organisms, living or dead

How do autotrophs produce their own nutrients?

They fix matter into organic compounds within chloroplast using solar energy, then store it

What are the two autotrophic adaptions for nutrient production?

The Calvin cycle and chemosynthesis

What is the Calvin cycle?

When carbon dioxide is fixated into glucose

What is chemosynthesis?

The oxidation of inorganic nutrients within bacteria and archaea to convert into energy sources

Where does chemosynthesis occur?

Ecosystems with little sunlight and a high concentration of inorganic compounds

How does chemosynthesis support ecosystems?

They provide energy for both themselves and their hosts

What an example of chemosynthesis?

When hydrogen sulfide at hydrothermal vents is oxidised to become sulphite, thiosulfate and elemental sulfur, ATP is released to convert CO2 into glucose

What is the equation for the oxidation of hydrogen sulfide?

18H2S + 6CO2 + 3O2 -> C6H12O6 + 12H20 =18S

What do heterotrophic adaptions modify?

How the nutrients are sourced, digested and absorbed.

What do heterotrophic adaptions depend on?

The organism's mobility

What are some adaptions for plant and fungi nutrient acquisition?

Their chemical digestion can efficiently breakdown dead matter, parasitic plants can invade vascular plant tissue to uptake some of their nutrients, carnivorous plants can decompose trapped living organisms when producing attractive physical or chemical signals.

What is the disadvantage for nutrient uptake in parasitic plants?

The possible transfer of RNA and pathogens

What are some morphological adaptions for animal nutrient acquisition?

Evolution of the mouth and limbs for prey capture and initial physical digestion

What are some chemical and mechanical adaptions for animal nutrient acquisition?

They digestive tract has become more specialised for more efficient energy collection, digestion and absorption

What are macronutrients?

The components of food that provide energy and are needed in large amounts and are used to construct macromolecules needed for energy production and storage

What are micronutrients?

Compounds needed in small amounts that help the plant and its enzymes function

What are coal factors?

Substances that aid with enzyme functioning

Where are macronutrients derived from?

The atmosphere and water

What form of carbohydrates can be used in glycolysis?

Glucose

What form of proteins can be used in glycolysis?

Digested amino acids

What form of lipids can be used in glycolysis?

Phosphorylated glycerol

How are different macronutrients differentiated against?

The food that is more nutritious can be detected by scent and smell

What are the macromolecules?

Carbohydrates, lipids and proteins

What is the purpose of macromolecule digestion?

To provide the energy the body uses

Why is nitrogen essential to plants?

They help form necessary proteins and nucleic acids

Why can't plants directly use atmospheric nitrogen?

They don't have the machinery to convert it into a usable form.

How do plants obtain nitrogen?

Prokaryotic organisms such as rhizobacteria perform nitrogen fixation

What is nitrogen fixation?

Converting atmospheric nitrogen into ammonia and then ammonia into nitrates

Are there some plants that can perform nitrogen fixation?

Yes, legumes have nodules to perform nitrogen fixation

What are nodules?

Specialised root structures

What are rhizobacteria?

Prokaryotes that live in association with plants in the soil

What is the symbiotic relationship between rhizobacteria and legumes?

Rhizobacteria forms nodules within legumes so nitrogen fixation can be facilitated them; legumes then provide nutrients to rhizobacteria for growth

What is the mutually beneficial relationship between fungi and plants?

Michaeli fungi receives nutrition from the plants and provides them with soil-stored nutrients, including phosphate, copper and zinc.

What are the disadvantages of metabolic processes?

They can produce toxic by-products

How are toxic by-products eliminated from the body?

Through excretion

What are the by products of cellular respiration?

CO2 and H2O

How do plant cells use the by-products of photosynthesis?

They recycle them to form the reactants for cellular respiration.

What is the disadvantage of recycling by-products in plant cells?

The constant production of reactants is products is not always needed.

Why do excess reactants or products need to be removed from the plant?

To maintain homeostasis

What are excess metabolic products and reactants called?

Waste

How is waste removed in plants?

Through transpiration

Where does transpiration occur?

In the stomata of leaves

How does transpiration occur?

When the stomata opens and water is evaporated, decreasing pressure is generated to draw up water through the stem and absorb water from the roots

What are the characteristics of stomatal opening regulation?

It is dynamic and reversible

What influences stomatal opening regulation?

Light, carbon dioxide levels, humidity and stress hormones

What other forms of waste removal are there besides transpiration in plants?

The use of lenticels

What are lenticels?

Permanently open pores on plant stems and within the bark of woody plants

What is the efficiency of lenticel waste removal in comparison to stomatal transpiration?

It is much less efficient because it results in very small removal

What other waste is present within plants (besides water and carbon dioxide)?

Nitrogenous wastes like ammonia and nitrate

How does ammonia and nitrate travel from rhizobacteria to the plant?

Through soil absorption and through xylem sap

What are nitrogenous waste products used for in plants?

They help with protein synthesis instead of being excreted.

This is why fertilisers often include nitrogenous waste

What is another form of excretion besides transpiration and lenticel removal?

Shedding

What is shedding?

The removal of unwanted metabolic waste molecules that have accumulated in a cell's vacuole. This occurs as the cell ages

What are some of the waste products removed in shedding?

Amino acids, mineral salts and water

When does stomatal respiration occur?

Only during the day

What happens when stomata is closed at night?

Water builds up in the plant tissue because it continues to absorb water from the soil due to root pressure

What is the process of plant excretion at night?

Guttation

How does guttation occur?

When excess waste is released in small droplets of xylem sap at the leaf's margin

What drives guttation?

Increased root pressure that drives xylem sap through hydathodes

What are hydathodes?

Secretory cells at the leaves epidermis

What role do heterotrophic fungi play in ecosystems?

They act detritivores or decomposers

How do heterotrophic fungi act as detritivores or decomposers?

They recycle their nutrients and return them to the soil to aid the growth of plants and enable the functioning of all organisms in an ecosystem

How do heterotrophic fungi obtain organic compounds?

From the substrates of non-living organic matter or absorbing their organic material across their cell walls

How do multicellular fungi obtain organic compounds?

They extend their hyphae (from their mycelium) into the food source

How does unicellular fungi obtain organic compounds?

They can colonise their food sources by releasing digestive enzymes into their sources of food for nutritional uptake

Where are the food sources accumulated in relation to the hyphae or fungi?

They are accumulated around them and can easily diffuse through the cell wall because they are so small

How are macromolecules and insoluble polymers digested by fungi?

The hyphae releases enzymes to break them down into easily diffusible products

How do animals initially physically digest foods?

Through the digestive tract

What are some adaptations of the digestive tract?

It contains lots of vascular tissue for nutrient transportation

What system transports digested compounds around the body?

The circulatory system

What is the digestive system of a sponge?

The water channels of sponges that can transport food particles to cells

What types of animals are sponges, cnidarians, and platyhelminths?

Simple animals

What is the digestive system of cnidarians, platyhelminths?

A single opening that transports food directly to the gut which produces digestive enzymes to absorb nutrients and excrete waste

What are the three sections of the digestive tract?

The foregut, the midgut and hindgut

What is the purpose of the foregut?

To take in and store the food and where initial chemical and mechanical digestion takes place

What does the midgut and hindgut facilitate?

Chemical digestion, nutrient absorption and waste excretion

What are the shapes and sizes of the digestive tract dependent on?

The diet of the organism

What is the diet of herbivores?

Plants that are hard to digest

How have the mechanical systems within the digestive tract adapted to the herbivore diet?

Their mouths have different parts for grinding, cutting, rasping and shredding, and their stomach has gained more muscles and extensions

What are the features of a herbivore's stomach?

The rumen, reticulum, omasum and abomasum

What is the purpose of the rumen?

Where food enters the mouth

What is the purpose of the reticulum?

It facilitates initial mechanical digestion, in which it regurgitates the food for the herbivore to chew in the mouth again; this process is called rumination.

What is the purpose of the omasum and abomasum?

The omasum helps to absorb water, nutrients and minerals and the abomasum helps to secrete enzymes for chemical digestion

What part of the digestive tract is the stomach a part of?

The foregut

How have the chemical systems within the digestive tract adapted to the herbivore diet?

The evolution of the abomasum

What are foregut fermenters?

Ruminant herbivores where most of the digestion occurs in the foregut

What are hindgut fermenters?

Herbivores that rely on a long hindgut (specifically the caecum) for digestion because the caecum contains microbes that can ferment the food.

What is the difference between foregut and hindgut fermenters?

Foregut fermenters are ruminants, whereas hindgut fermenters are not

What is the diet of carnivores?

Animal tissue

What type of digestion are carnivores more reliant on?

Chemical digestion

What are the mechanical adaptations of carnivores?

Sharp teeth to shear through animal tissue easily

What are the chemical adaptations of carnivores?

Their mouths contain salivary enzymes, their foregut and stomach are extremely acidic so proteins can be digested and their midgut secretes bile for lipid digestion and absorption

Compare carnivore and herbivore digestive tracts.

Carnivore tracts are shorter and less complex because they don't need to store food within their tract.

When does absorption of nutrients occur?

When nutrients are diffused into the absorptive tissue in the digestive tract and transported around the body.