Section 1: Variety of organisms Flashcards
characteristics and variety of living organisms, levels of organisation, cell structure
What are the 8 characteristics of living organisms
Movement, reproduction, sensitivity, homeostasis, growth and development respiration, excretion, nutrition
What is sensitivity
the ability to respond to a stimulus
what is homeostasis
they way an organism can maintain a constant internal environment
what is respiration
a chemical reaction by which organisms release energy from food normally using oxygen
what is excretion
removing waste products that have been produced by the body such as carbon dioxide and urea, this doesn’t include faeces
What are the organelles within of a plant cell
cell wall, cell membrane, cytoplasm, mitochondria, chloroplasts, ribosomes, nucleus, vacuole
What are the organelles within an animal cell
nucleus, cell membrane, cytoplasm, ribosomes, mitochondria
Give a description of the properties of a plant cell
- Can carry out photosynthesis and contain chloroplasts
- There cell walls are made out of cellulose
-They store carbohydrates as starch or sucrose - They are multicellular
Give an example of a plant
Maize, peas or beans
Give a description of the properties of an animal cell
- they are multicellular
- they have nervous coordination
- Store carbohydrates as glycogen
- cant photosynthesise
What is nervous coordination
The ability to respond rapidly to the changes in the environment
What are the organelles within a fungi cell
cell membrane, cellwall, cytoplasm, nucleus, food storage granules
Give a description of the properties of a fungi cell
- They can be either single or multicellular
- Cant photosynthesise
- Their body is called a mycelium which is made up of thread like structures called hyphae, which contain nuclei
- Their cell walls are made from chitin
- they store carbohydrates as glycogen
-They feed by saprotrophic nutrition
What is saprotrophic nutrition
When a cell secretes extracellular enzymes into the area outside their body to dissolve their food so they an absorb the nutrients
Give an example of a fungi
Yeast (single cellular)
Mucor (multicellular)
What are the organelles within a Protoctist cell
nucleus, flagella, mitochondria, food storage granules, cell surface membrane, cell wall, (chloroplasts)
Give a description of the properties of a protoctist cell
- they are single celled microscopic
- some contain chloroplasts and photosynthesise like a plant cell
- some are more like animal cells
Give an example of a protoctist
amoeba (animal cell like and lives in pond water)
chlorella (plant cell like)
Plasmodium (causes malaria and a pathogen)
What are the organelles within a bacteria cell
cell wall, cell membrane, cytoplasm, plasmids, circular chromosome, slime capsule, flagella
Give a description of the properties of a prokaryotic organisms such as bacteria
- they are single celled and microscopic
- they don’t have a nucleus
- contain a circular chromosome containing DNA
- some bacteria can photosynthesise
- most bacteria feed off other organisms living or dead
give an example of a bactreia/prokaryote
- Lactobacillus bulgaricus ( rod shaped and used to turn milk to yoghurt)
- Pneumococcus (spherical bacterium that causes pneumonia)
- Plasmodium (A pathogenic example, responsible for causing malaria.)
What does the term pathogen mean?
A pathogen is an organism which causes disease
Different types of pathogens
Fungi, protoctists, viruses (not organism) and bacteria
Give a description of the properties of a virus
- not living organisms
- they are parasitic and can only reproduce inside living cells
- they infect every type of living organism
- they are small particles- smaller than bacteria
What is the structure of a virus
-Wide variety of shapes and sizes
- no cellular structure
- have a protein coat
- contains either DNA or RNA
What is tobacco mosaic virus
A virus that causes the discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts
Give an example of a virus
- Influenza virus that causes flu
- HIV virus that causes AIDS
Nucleus functions
- Controls the cells activities
- Contains DNA/ chromosomes
Cell membrane function
- Forms a barrier between cytoplasm and outside the cell
- Controls what enters and leaves the cell
Cytoplasm functions
- jelly like substance where chemical reaction occur
- contains enzymes and the cells organelles
Mitochondria function
- Carries out aerobic respiration in cells and provides energy for the cell
Ribosomes function
- Site where proteins are made in a cell (protein synthesis)
Chloroplasts function
-Absorb light to make food for the plant through the process of photosynthesis
- Contains a green pigment called chlorophyll
Vacuole functions
- contains cell sap which is full of dissolved sugars, mineral ions and other solutes
- surrounded by the vacuole membrane
Cell wall functions
- made of carbohydrate called cellulose
- it is rigid and keeps cell shape
- fully permable
What are similarities between plant and animal cells
They both have:
- Mitochondria
- Cytoplasm
- Nucleus
- Cell membrane
- Ribosomes
What are differences between plant and animal cells
Plants have a permanent vacuole whilst animals do not.
Plants have a cell wall whilst animals do not
Plants can photosynthesise
What are the levels of organisation
Organelles -> cells -> tissues -> organs -> organ system -> organism
Cell definition
- they are the smallest unit
- contain many different organelles ( tiny structures within a cell that carries out specific functions)
Tissue definition
a group of the same cells that work together to carry out a particular function
Organ definition
collection of several different tissues working together to carry out a more complex function
organ system definition
several different organs working together to make up an organism
What is a specialised cell
A cell that is specialised to carry out a particular function
What is cell differentiation
The process by which a cell becomes specialised
What is a stem cell and where can they be found
- Undifferentiated cells that have the ability to become specialised
- you can get a lot of stem cells from early human embryos
- Adults do have a few stem cells but are only found in certain places such as bone marrow and can only only turn into a few types of cell
Uses of stem cells
- Stem cells can be cloned in a lab and made into specialised cells to be used in medicine or research
- In stem cell therapy stem cells can repair damaged tissue
Advantages of stem cells
- used to cure diseases such as diabetes as stem cells can be injected to replace the faulty ones
- end our reliance on organ donation
- benefit burn victims
Disadvantages of stem cells
- wasting potential human life
- concentrate more time to finding and developing other sources of stem cells
Give an example of a protoctist, bacteria, and virus which are all pathogens
Protoctist: plasmodium which causes malaria
Bacteria: Pneumococcus which cause pneumonia
Virus: Influenza which causes flu
