characteristics of living organisms Flashcards
What acronym helps remember the characteristics of living organisms?
MRS C GREN
MRS C GREN stands for Movement, Respiration, Sensitivity, Control, Growth, Reproduction, Excretion, and Nutrition.
What is the term for organisms that create their own food?
Autotrophic
Autotrophs use processes like photosynthesis to produce their own energy.
What is the process by which plants produce energy?
Photosynthesis
Plants use sunlight, carbon dioxide, and water to produce glucose and oxygen.
What is the term for organisms that consume other living organisms for energy?
Heterotrophic
Heterotrophs obtain energy by consuming a variety of food sources.
What is respiration in living organisms?
A chemical reaction that releases energy from glucose
This can occur aerobically (with oxygen) or anaerobically (without oxygen).
What are the waste products of aerobic respiration?
Carbon dioxide and water
These are produced as waste products during the respiration process.
What does excretion involve?
The removal of toxic materials from organisms
Excretion is distinct from egestion, which involves the removal of undigested food.
What is sensitivity in living organisms?
The ability to detect and respond to stimuli
This is crucial for an organism’s survival.
How do plants respond to gravity?
Geotropism
Roots grow downwards in response to gravitational pull.
What is homeostasis?
The regulation of internal conditions within required limits
Homeostasis is vital for maintaining stable conditions in organisms.
What is the optimum human body temperature?
37°C
Mechanisms like sweating help maintain this temperature.
What is the difference between sexual and asexual reproduction?
Sexual reproduction involves two gametes, while asexual reproduction involves a single parent
Sexual reproduction results in genetic variation; asexual reproduction produces clones.
What is a defining feature of eukaryotic organisms?
They contain a nucleus with a distinct membrane
Eukaryotes include animals, plants, fungi, and protoctists.
What are the five kingdoms of living organisms?
Animals, Plants, Fungi, Protoctists, Prokaryotes
These kingdoms represent the main classifications of life.
What is a significant characteristic of prokaryotic organisms?
They are always single-celled and lack a nucleus
Prokaryotes include bacteria.
What is the method of feeding for fungi?
Saprotrophic nutrition
Fungi secrete enzymes onto food to absorb nutrients.
What are two examples of protoctists?
Amoeba, Paramecium
Protoctists can be single-celled and some have features similar to plants or animals.
What is the role of mitochondria in cells?
Site of aerobic respiration
Mitochondria release energy for cellular processes.
Fill in the blank: The process of _______ describes the growth of roots towards gravity.
Geotropism
True or False: All eukaryotic cells have chloroplasts.
False
Only plant cells contain chloroplasts for photosynthesis.
What is the primary function of ribosomes?
Site of protein synthesis
Ribosomes are essential for building proteins in cells.
What type of reproduction do bacteria typically use?
Asexual reproduction
Bacteria reproduce by binary fission, creating clones of themselves.
What are the components of prokaryotic cells?
Cell wall, cell membrane, cytoplasm, plasmids, circular DNA
Prokaryotic cells lack membrane-bound organelles.
What is the primary characteristic of prokaryotic cells?
They lack a nucleus and have genetic material in the cytoplasm.
Prokaryotes include bacteria and archaea.
What are saprobionts?
Organisms that feed on dead organic matter.
Also known as decomposers.
What are the components found in prokaryotic cells?
- Cell wall
- Cell membrane
- Cytoplasm
- Plasmids
- Circular DNA
What is a pathogen?
A microorganism that causes disease in another organism.
Which microorganisms can be classified as pathogens?
- Bacteria
- Fungi
- Protoctists
- Viruses
What disease does M. tuberculosis cause?
Tuberculosis (TB) in humans.
What is the common effect of tuberculosis?
Chronic cough and bloody mucus.
What is the primary impact of Black Sigatoka on banana plants?
Reduces their ability to photosynthesize.
What is a characteristic of viruses?
They are parasitic and can only reproduce inside living cells.
True or False: Viruses are considered living organisms.
False.
What is the only life process that viruses display?
Reproduction.
What disease is caused by the HIV virus?
Acquired Immunodeficiency Syndrome (AIDS).
What are the symptoms of HIV in its initial stage?
Flu-like illness.
How can HIV be transmitted?
- Direct sexual contact
- Exchange of bodily fluids
- From mother to child during birth or in breast milk
Which influenza virus is responsible for the most cases of flu globally?
Influenza A.
What is the tobacco mosaic virus (TMV) known for?
Causing discolouration of the leaves on tobacco plants.
Fill in the blank: The virus can stay in the soil for about ______.
50 years.
What is the best method of control for tobacco mosaic virus?
Good field hygiene.
What happens to plants infected with the tobacco mosaic virus?
They will not grow as much due to lack of photosynthesis.
What is the structure of a typical virus?
They have a protein coat and contain one type of nucleic acid, either DNA or RNA.
What is a common symptom of influenza viruses?
High temperature, body aches, and fatigue.
