variety of life

multicellular organisms

made up of many different types of cells

how do legumes (eg peas, beans, clovers) help soil fertility?

farmers use crop rotation by growing legumes for a season. These have nitrogen-fixing bacteria in their root nodules, which can convert nitrogen into nitrates (nitrogen-fixation). This improves nitrate content of soil. As plant and bacteria benefit, this is an example of symbiosis

what are the two categories of animals?

vertebrates and invertebrates

what are the main characteristics of a mammal?

give birth to live young

feed offspring on milk

have fur

what type of cells do all fungi have?

eukaryotic

do fungi cells contain chloroplasts?

NO NEVER

what does heterotrophic mean?

can’t make their own food, so must get energy and carbon by consuming other organisms

what are fungi’s cell walls made of?

chitin

how do yeast reproduce?

asexually

what are the main two ways in which humans use yeast cells?

brewing and baking

describe the structure of a toadstool or mushroom

the ‘cap’ is its fruiting body, the reproductive structure from where the spores are released. However, the rest of the fungus is underground. A mass of thread-like hyphae, which form a complex network (mycellium)

what type of structure are hyphae?

multinucleate

what does multinucleate mean?

there is no division into individual cells, so cytoplasm contains many nuclei

sapotrophism

a type of feeding where there are decomposers breaking down dead organisms

how does sapotrophism work?

extra-cellular digestive enzymes are secreted from the hyphae onto the food, breaking it down. The hyphae then absorb the products of digestion for use in respiration, growth and reproduction/spore formation

how does bread become mouldy?

spores land on bread

hyphae grow from spores

mycellium forms

enzymes break down the bread

mould grows → fruiting bodies

what are the benefits of fungi?

decomposers recycle minerals

baking and brewing

penicillin antibiotic is made using penicillin fungus

what are the negative’s of fungi?

athlete’s foot

ringworm

thrush

spoiling of food

what is the kingdom protoctista?

organisms that are microscopic and single celled

how does the pseudopodia help with movement?

membrane can ‘stretch’ and fill with cytoplasm

how does the pseudopodia help with feeding

can extend and engulf smaller organisms/food

explain the role of the food vacuole

releases enzymes to break down ‘food’

state the function of the contractile vacuole

excretes water and waste

what are plant like protoctistans called?

algae (contain chloroplasts so photosynthesise)

what disease is caused by plasmodium protozoan/protoctistan?

malaria

what human body cells does Plasmodium invade?

liver and rbc

how is plasmodium transferred between host organisms?

mosquito bites an infected person → parasite inside mosquito. This mosquito bites an uninfected person, transferring the parasite

what makes a cell prokaryotic?

no membrane bound organelles

what type of cells are bacteria

prokaryotic

what are the three different types of bacteria cell?

rod-shaped bacilli, spherical cocci and spiral spirochetes

what are bacteria’s cell walls made of?

mucopolysaccharides (a mix of protein and carbohydrates)

how is DNA stored in bacteria?

a single long chromosome and, in many bacteria, small circles of DNA called plasmids which play an important role in DNA engineering

how is yoghurt produced?

sterilise kit (dilute bleach or steam)

pasteurise milk (heat to 70 degrees celsius)

introduce lactobacillus bacteria and incubate at around 37-44 degrees for 3-6 hours

fermentation. Bacteria uses lactose for respiration and produces lactic acid - lowers pH, denatures milk proteins and thickens the milk

cool down in a fridge