biology basics Flashcards
describe the levels of organisation in organisms
organelles, cells, tissues, organs and systems
describe cell structures
nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole
what are differences in the structure of plant and animal cells
plant cell has vacuole, cell wall, chloroplasts
what is the role of enzymes
biological catalysts
what are plant cell walls made of
cellulose
what do plants store carbohydrates as
sucrose/starch
what do humans store carbohydrates as
glycogen
describe bacteria
microscopic single-celled organisms;
cell wall, cell membrane, cytoplasm and plasmids;
no nucleus but contain a circular chromosome of DNA; some carry out photosynthesis
most feed off other living or dead organisms.
examples of bacteria
Examples include Lactobacillus bulgaricus, a
rod-shaped bacterium used in the production of yoghurt from milk, and
Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia
plants
multicellular organisms;
cells contain chloroplasts
carry out photosynthesis;
cellulose cell walls;
store carbohydrates as starch or sucrose.
examples of plants
Examples include flowering plants, such as a
cereal (for example, maize), and a herbaceous legume (for example, peas or beans)
animals
multicellular organisms;
cells do not contain chloroplasts and are not able to carry out photosynthesis;
they have no cell walls;
they usually have nervous co-ordination
can move from one place to another;
they often store carbohydrate as glycogen.
fungi
no photosynthesis;
mycelium made from thread-like structures called hyphae, which contain many nuclei;
some are single-celled;
cell walls made of chitin;
feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products;
( saprotrophic nutrition);
they may store carbohydrate as glycogen.
examples of fungi
Examples include Mucor, which
has the typical fungal hyphal structure, and yeast, which is single-celled.
protoctists
microscopic single-celled organisms. Some, like Amoeba, have features like an animal cell, while others, like Chlorella, have chloroplasts and are more like plants.
example of pathogenic protoctist
A pathogenic example is Plasmodium,
responsible for causing malaria.
viruses
not living organisms. smaller than bacteria;
can reproduce only inside living cells;
they infect every type of living organism.
wide variety of shapes and sizes;
no cellular structure but have a protein coat and contain either DNA or RNA.
examples of viruses
Examples include the tobacco mosaic virus that causes
discolouring of the leaves of tobacco plants by preventing the formation of
chloroplasts, the influenza virus that causes ‘flu’ and the HIV virus that causes AIDS.
how do fungi decompose wood
- hyphae / mycelium secrete enzymes onto wood
2) they digest material, producing carbon dioxide / water
(saprotrophyte example)
define organelle
a specialized structure within a cell
define tissue
a group of similar cells that work together to carry out a particular function
define organ
group of different tissues tat work together to perform a function
how does temperature affect enzymes
increase temp=increase activity
until they denature
what happens when enzymes denature
the enzyme changes shape so the substrate no longer fits
