Characteristics of Living Organisms Flashcards
(40 cards)
1
Q
Characteristics of living organisms
A
- Movement:
- Respiration:
- Sensitivity:
- Control:
- Growth:
- Reproduction:
- Excretion:
- Nutrition:
2
Q
Movement
A
- Movement: Action causing a change of position or place.
- Locomotion: Movement from place to place (in organisms).
- Plants: Can’t move place to place, but can change orientation.
3
Q
Control
A
Homeostasis: The control of an organism’s internal environment to keep conditions within required limits.
4
Q
Homeostasis in humans
A
- Thermoregulation: Control of body temperature (optimum 37°C).
- If too high: Sweating, vasodilation cool the body.
- Glucoregulation: Blood glucose control
- Osmoregulation: Water level control
5
Q
Homeostasis in plants
A
Transpiration: Water evaporates from stomata (leaf underside), cooling the plant.
6
Q
Reproduction
A
- Reproduction: Produces more of the same organism, vital for species survival.
- Types: Sexual and asexual.
7
Q
Sexual Reproduction
A
- Male and female gametes fuse.
- Humans: Sperm + egg
- Plants: Pollen + ovule
- Offspring DNA: Mix of maternal and paternal.
8
Q
Asexual Reproduction
A
- Asexual reproduction: One parent, offspring are clones (identical DNA).
- Example: Mitosis
- Plants: Tubers, budding, runners
- Single-celled organisms: Bacteria, amoeba
9
Q
Growth
A
- Growth: Permanent increase in size.
- Animals: Grow from zygote to adult, changing shape.
- Plants: Grow throughout life with new shoots, leaves, and branches.
10
Q
Nutrition
A
- Nutrition: Organisms get food for energy.
- Energy needed for: Movement, respiration, excretion, and other life processes.
11
Q
Nutrition in Plants
A
- Photosynthesis: Plants use sunlight, CO₂, and water to make glucose and oxygen.
- Plants are autotrophic: They make their own food.
12
Q
Nutrition in Animals
A
- Heterotrophic: Animals consume other organisms for energy.
- Digestion: Break down complex molecules into simpler ones.
13
Q
Respiration
A
- Respiration: Chemical reaction in all living organisms.
- Types: Aerobic (with oxygen) or anaerobic (without oxygen).
- Waste products: Carbon dioxide and water.
- Energy form: ATP
14
Q
Excretion
A
- Excretion: Removal of toxic waste products from the body.
- Metabolic reactions: Produce waste, some toxic, that must be eliminated.
15
Q
Excretion in Animals
A
- Carbon dioxide: From respiration
- Water: From respiration and chemical reactions
- Urea: From protein breakdown (contains nitrogen)
16
Q
Excretion in Plants
A
- Oxygen: From photosynthesis
- Carbon dioxide: From respiration
- Water: From respiration and chemical reactions
17
Q
Response to Surroundings
A
- Sensitivity: Organism’s ability to detect and respond to stimuli in its surroundings.
- Importance: Helps increase chances of survival.
18
Q
Sensitivity responses in animals
A
- Nervous system (humans): Uses receptors, neurons, and effectors with electrical impulses to detect and respond to stimuli.
- Endocrine system: Uses hormones (chemical messengers) in the blood to respond to stimuli.
19
Q
Sensitivity responses in plants
A
- Controlled by chemicals: Slower than animals.
- Geotropism: Roots grow downwards in response to gravity.
- Phototropism: Shoots grow towards light.
20
Q
What are the five kingdoms of life?
A
- Plants
- Animals
- Fungi
- Protoctists
- Bacteria
21
Q
Description of Plants
A
- Multicellular
- Have chloroplasts → can photosynthesise
- Have cell walls made of cellulose
- Store carbohydrates as sucrose or starch
22
Q
Examples of Plants
A
- Flowering plants like:
- Cereals (e.g. maize)
- Herbaceous legumes (e.g. peas and beans)
23
Q
Description of Animals
A
- Multicellular
- No chloroplasts → can’t photosynthesise
- No cell walls
- Have nervous coordination → respond quickly to environment
- Usually move from place to place
- Store carbohydrates as glycogen
24
Q
Examples of Animals
A
- Mammals (e.g. humans)
- Insects (e.g. houseflies, mosquitoes)
25
Description of Fungi
- Some are single-celled
- Others have a mycelium made of hyphae with many nuclei
- Can’t photosynthesise
- Cell walls made of chitin
- Use saprotrophic nutrition (release enzymes to digest food externally)
- Store carbohydrates as glycogen
26
Examples of Fungi
- Yeast → single-celled
- Mucor → multicellular with mycelium and hyphae
27
Description of Protoctists
- Single-celled and microscopic
- Some have chloroplasts and are like plant cells
- Others are more like animal cells
- Some have cellulose cell walls
28
Examples of Protoctists
- Chlorella – plant-like
- Amoeba – animal-like, lives in pond water
29
Description of Bacteria
- Single-celled and microscopic
- No nucleus
- Have circular DNA (chromosome) and small circles of DNA called plasmids
- Some can photosynthesise
- Most feed off other organisms (living or dead)
- Peptidoglycan/ murein cell wall
30
Examples of Bacteria
- Lactobacillus bulgaricus – used in yoghurt-making, rod-shaped
- Pneumococcus – spherical (causes pneumonia)
31
Description of Viruses
- Not cells – they are particles, smaller than bacteria
- Can only reproduce inside living cells (they are parasites)
- Infect all types of organisms
- Come in different shapes and sizes
- No cellular structure – made of a protein coat around genetic material like DNA or RNA
32
Examples of Viruses (Plants and Animals)
- Influenza virus – causes flu
- Tobacco mosaic virus – affects plants (discolours leaves by stopping them from forming chloroplasts)
- HIV – causes AIDS
33
What is a pathogen?
A Pathogen is a disease causing microorganism.
34
Examples of Pathogenic Bacteria
- Pathogenic bacteria: Can stay in body cavities without infecting cells.
- M. tuberculosis: Causes TB in humans, infects lungs, leads to cough and bloody mucus.
- Associated with: Poor hygiene and sanitation.
- M. bovine: Found in cows, can transmit TB to humans.
35
Examples of Pathogenic Fungi
- Cattle ringworm & athlete's foot: Affect skin surface.
- In plants: Can threaten crops.
- Black Sigatoka (bananas): Affects leaves, reducing photosynthesis, causing black streaks, and eventually killing the leaf.
36
Examples of Pathogenic Protoctists
- Plasmodium falciparum: Protoctist causing severe malaria.
- Spread by vector: Mosquitoes
- Symptoms: Fever, chills, fatigue
37
What are bigger, protoctists or bacteria?
Bacteria
38
How can pathogens be spread?
- Insects / animals / bites / vectors
- Contaminated food
- Contaminated water
- Touch
- In the air / coughs / sneezes / droplets
39
Is there a cure for HIV?
There is no cure for HIV, although the use of antiretroviral drugs used early in the infection can now effectively control the disease to slow or halt the progress to AIDS
40
Eukaryotic vs Prokaryotic Cells
- They are single-celled
- They contain no membrane bound organelles (excluding ribosomes)
- The nuclear material is found in the cytoplasm
- Smaller in size
