1A-1B NATURE AND VARIETY OF LIVING ORGANISMS

features of plant cells

• multicellular

• contains chloroplasts, which help carry out photosynthesis

• cellulose cell walls

• stores carbs as starch or sucrose

• e.g. flowering plants (maize), herbaceous legumes (peas, beans)

features of animal cells

• multicellular

• doesn’t contain chloroplasts, no photosynthesis

• no cell walls

• usually have nervous co-ordinaiton so can move from one place to another

• usually stores carbs as glycogen

features of protoctist cells

• single-celled

• microscopic

• amoeba → live in water, animal-like

• chlorella → contains chloroplasts, plant-like

• plasmodium → pathogen, causes malaria

features of fungi

• some single-celled

• cannot photosynthesize

• body usually organized into a mycelium made from thread-like structures called hyphae, which contain nuclei

• chitin cell walls

• saprotrophic - feed via extracellular secretion of digestive enzymes onto food + the absorption of organic products

• stores carbs as glycogen sometimes

• e.g. yeast (single-celled), mucor (hyphae)

features of bacteria

• single celled

• microscopic

• contains cell wall, cell membrane, cytoplasm + plasmids

• no nucleus but contains plasmids (small circular loops of DNA)

• some can photosynthesize, but most feed off other living/dead organisms

example of bacteria

• lactobacillus → rod-shaped, used in yoghurt production

• pneumococcus → spherical bacterium which acts as the pathogen causing pneumonia

what are pathogens + what do they include

• disease-causing micro-organism

• could include bacteria, fungi, protoctists, viruses

features of viruses

• not living as doesnt MRS C GREN

• smaller than bacteria

• can only reproduce inside living cells - parasitic

• can infect every type of organism

• no cellular structure but have a protein coat and contain one type of nucleic acid (DNA or RNA)

examples of viruses

• tobacco mosaic virus → discollours tobacco leaves

• HIV → causes AIDS

• influenza → causes flu

features of eukaryotes

• cell membrane

• cytoplasm

• genetic material in NUCLEUS

• nucleus

• SOME have cell walls

features of prokaryotes

• cell membrane

• cell walls

• cytoplasm

• genetic material in CYTOPLASM

• NO nucleus