Unit 1: The Nature and Variety of Organisms Flashcards
What are the the eight basic characteristics all living organisms have
Nutrition, Respiration, Excretion, Response/Sensitivity, Movement, Control, Reproduction, Growth/Development
Why do they need nutrition
To be provided with energy and the raw materials for growth and repair
What is respiration
The transfer of energy from glucose, this process goes on in every cell of your body
What is excretion and give examples
Excretion is the removal of waste products from the body.
.CO2 is a waste product from the lungs
.Sweat is a waste product from the skin
.Excretion is also carried out by the kidneys
What is response
Living organisms can react to changes in their surroundings
What is movement
Moving towards things such as water and food, and away from things such as predators and poisons.
What is control
Balancing body functions to maintain a “constant internal environment”(homeostasis)
What is reproduction
Organisms passing on their genes to offsprings
What is growth and development
Increasing in size and mass using materials from food
What are living organisms made of
Cells
What are eukaryotic cells
Complex cell structures
Two examples of eukaryotic cells
.Animal cells
.Plant cells
.Fungi
What are prokaryotic cells
Simple, small structured cells
Two examples of prokaryotic cells
.Protoctists
.Bacteria
.Viruses
Explain 3 features in an animal cell
Nucleus: An organelle that contains DNA that controls the cells activities and is surrounded by its own membrane.
Cell membrane: Forms on the outer surface of the cell and controls the substances that go in and out.
Cytoplasm: A gel-like substance where most of the cells chemical reactions take place. It contains enzymes that control these reactions.
Mitochondria: Small organelles where most of the reactions for aerobic respiration take place.
Ribosomes: Small organelles where proteins are made in the cell
Explain 3 features in plant cells that are not found in animal cells
Chloroplast: Contains chlorophyll, the pigment used to absorb sunlight for photosynthesis
Cell wall: A rigid structure made of cellulose, which surrounds the cell membrane. It supports and strengthens the cell
Vacuole: A large organelle that contains cell sap that helps to support the cell
What are fungi
.Some are single-celled while others have a body called a mycelium that is made up of hyphae.
.They can’t photosynthesize
.They have cell walls made of chitin
.Most are fed by saprotrophic nutrition.
They can store carbohydrates as glycogen
Hyphae: A thread like structure that contains lots of nuclei
Saprotrophic nutrition: They secrete extracellular enzymes into the area outside their body to dissolve their food, so they can then absorbe the nutrients.
One example of a single celled fungus and one example of a multicellular fungus
.Yeast: Single-celled fungus
.Mucor: A multicellullar fungus with a mycelium and hyphae
What are protoctists
.They are single celled and microscopic
.Some have chloroplasts and are similar to plant cells
.Others are similar to animal cells
Give a similarity each protoctists have to plant cells and animal cells and give two examples
.Amoeba(Animal cells): Does not have a cell wall and is free to move
.Chlorella(Plant cells): Contains chlorophyll
Amoeba: A cell that lives in pond water
Chlorella: A plant like cell
What is bacteria
.Single celled microscopic organisms
.They don’t have a nucleus
.They don’t have a circular chromosome of DNA
.Some can photosynthesize
.Most bacteria feed off other organisms, both living and dead
What similarities and differences do bacterium have with animal cells and/or plant cells
.Difference:
-Bacterium have no nucleus
-Don’t have a circular chromosone of DNA
-Feed off other organisms
Similarity:
-Some can photosynthesis
-Have a cell wall
-Have cytoplasm
What are viruses
.These are particles rather than cells and are smaller than bacteria
. They can only reproduce inside living cells
.They infect all types of living organisms
.They come in many different sizes and shapes
.They don’t have a cellular structure- They have a protein coat around some genetic material (either RNA or DNA)
A virus is a parasite, it depends on other organisms to grow/produce
What features make a virus different from most organisms
.They are particles rather than cells
.They depend on another organism to grow and reproduce
. Does not have a nucleus
What are pathogens
Pathogens are organisms that cause diseases
Examples of pathogens
Protoctists: Plasmodium, which causes malaria
Bacterium: Pneumococcus, which causes pneumonia
Viruses:
-Influenza virus which causes flu
-HIV whic causes AIDS
What are enzymes
Enzymes are biological catalysts that increase the speed of reactions in the body
Catalyst: Increate the rate of reaction without being changed or used
How do enzymes help the body
Enzymes reduce the need for high temperatures, as well as speeding metabolic reactions
What are enzymes made of
Enzymes are made of proteins, and all proteins are made of chains of amino acids.
Explain the process of enzymes
.Chemical reactions involve things either being split apart or joined together
. A substrate is a molecule that is changed in a reaction
.Every enzyme molecule has an active site
.Every enzyme only speeds up one reaction, this is because for the enzyme to work a substrate has to be the perfect shape to fit into the active site
Active site: Where a substrate joins onto an enzyme
What two environmental features affect enzymes
Temperature and pH
How does temperature affect enzyme function
.Change in temperature affects the rate of enzyme-catalyste reactions
.As temperature increases the enzymes and substrates have more energy, causing them to move around more and are then more likely to collide and form enzyme-substrate complexes
.The optimal temperature is the temperature where enzymes are most active
.If the temperature goes above the optimal temperature the active site of the enzymes will become denatured, meaning the substrates no longer fit into the active site.
How does pH affect enzyme function
If the pH is too high or too low the enzymes active site can also become denatured
What is diffusion
The movement of particles from an area of high concentration to an area of low concentration until equilibrium is reached
What is osmosis
Osmosis is the net movement of water molecules from an area of high water concentration to an area of low water concentration across a partially permiable membrane until equilibrium is reached
What is active transport
The movement of particles from an area of low concentration to an area of high concentration
