10 Questions
What is the main difference between the cell structure of bacteria and eukaryotic organisms?
Bacteria are prokaryotic, lacking a true nucleus, while eukaryotic organisms have a true nucleus and membrane-bound organelles.
Which mode of nutrition is characteristic of fungi?
Saprophytic
What is the primary function of mitochondria in cells?
To generate energy for the cell through cellular respiration
What is a beneficial role of bacteria in the environment?
Decomposers, breaking down organic matter and recycling nutrients
How do protocists reproduce?
Binary fission, multiple fission, or conjugation
What is a characteristic feature of viruses?
They lack cellular organelles and are obligate parasites
What is the function of chloroplasts in plant cells?
To produce glucose through photosynthesis
What is the primary source of energy for autotrophic organisms?
Light energy from the sun
What is the main difference between heterotrophic and autotrophic nutrition?
Heterotrophs obtain energy by consuming other organisms, while autotrophs produce their own energy through photosynthesis or chemosynthesis
What is the role of ribosomes in cells?
To synthesize proteins
Study Notes
Viruses
- Can infect plants, animals, and bacteria (bacteriophages)
- Have no cellular structure, but consist of a protein coat and one type of nucleic acid (DNA or RNA)
- Lack a nucleus, cytoplasm, and cell membrane
- Sometimes have a membrane called an envelope, which contains lipoproteins and glycoprotein receptors
- Envelope is not produced by the virus, but is stolen from the host cell's surface membrane
Advantages of Viruses
- Used to make vaccines
- Used as gene delivery vehicles (vectors) for gene therapy to cure genetic diseases
- Used to create a genomic library (collection of DNA from a single organism)
Disadvantages of Viruses
- Pathogenic to plants, animals, and bacteria
- Examples: tobacco mosaic virus, influenza virus, HIV, and others
Bacteria
- Obtain food through decomposition (saprophytic), parasitism, or symbiosis
- Reproduce through asexual reproduction by binary fission
- Can divide into 2 every 20 minutes under favorable conditions
Advantages of Bacteria
- Decomposition and recycling of dead organisms and waste products
- Used in food industry (alcoholic fermentation, dairy industry)
- Produce human hormones through genetic engineering
- Help plants fix nitrogen by living on roots of leguminous plants
Disadvantages of Bacteria
- Act as pathogens, causing diseases such as pneumonia, typhoid, and cholera
- Produce greenhouse gases, contributing to pollution and global warming
- Cause spoilage of food through decomposition
Comparison of Features of Living Organisms
- Bacteria: prokaryotic, unicellular, has cell wall, no chloroplasts, no mitochondria, has ribosome
- Animals: eukaryotic, multicellular, no cell wall, has mitochondria, has ribosome
- Plants: eukaryotic, multicellular, has cell wall, has chloroplasts, has mitochondria, has ribosome
- Fungi: eukaryotic, multicellular, has cell wall, has mitochondria, has ribosome
- Protoctists: eukaryotes, unicellular or multicellular, has cell wall (some), has chloroplasts (some), has mitochondria, has ribosome
Learn about the structure and characteristics of viruses, including bacteriophages, and how they differ from cellular organisms.
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