Variety Of Living Organisms & Structure Flashcards
What is the structure of the bacterial nucleus?
Bacteria lack a nucleus and instead have a circular chromosome of DNA.
What makes up the cell walls of bacteria?
Bacterial cell walls are made of polysaccharides and proteins.
What are small extra circles of DNA in bacteria called?
Small extra circles of DNA in bacteria are called plasmids.
Can bacteria carry out photosynthesis, or how do they primarily obtain nutrients?
Some bacteria can carry out photosynthesis, but most feed off other living or dead organisms.
What is a common characteristic of bacteria in terms of size and structure?
Bacteria are microscopic single-celled organisms.
What role do bacteria play in ecosystems?
Bacteria are decomposers, breaking down organic matter.
Provide examples of rod-shaped bacteria.
Examples include Escherichia Coli (E. Coli) commonly found in animal intestines and Lactobacillus Bulgaricus.
Name a spherical bacterium and its role.
Pneumococcus is a spherical bacterium that acts as the pathogen causing pneumonia.
What are protoctists, and why are they sometimes called the ‘dustbin kingdom’?
Protoctists are single-celled organisms, sometimes referred to as the ‘dustbin kingdom’ because they are a mixed group that doesn’t fit into plants, animals, or fungi.
How do some protoctists, like Amoeba, resemble animal cells?
Some protoctists, such as Amoeba, have features similar to animal cells.
Which protoctists have chloroplasts and share similarities with plants?
Some protoctists, like Chlorella, have chloroplasts and exhibit characteristics more akin to plants.
Are all protoctists harmless, or do some act as pathogens?
Some protoctists, like Plasmodium, function as pathogens, causing diseases such as malaria.
Are viruses living organisms?
Viruses are not living organisms; they are small particles.
Which types of organisms can viruses infect?
Viruses are capable of infecting every type of living organism
How do viruses reproduce, and where does this process occur?
Viruses can only reproduce inside living cells, taking over the host’s genetic machinery.
Describe the cellular structure of viruses.
Viruses do not have a cellular structure
What types of nucleic acid do viruses contain?
Viruses contain either DNA or RNA, but not both.
Do viruses exhibit specific characteristics of living organisms, except for one?
Viruses do not carry out characteristics specific to living organisms except for reproduction.
How do viruses reproduce, and what is the key step in this process?
Viruses reproduce by entering host cells, taking over the genetic machinery, and using it to produce more virus particles.
Name examples of viruses and their associated effects.
Examples include Tobacco Mosaic Virus (discolors tobacco leaves), Influenza Virus (causes flu), and HIV (causes AIDS).
What is the role of the nucleus in cells, and what is it composed of?
The nucleus determines cell behavior and contains chromosomes made of DNA.
Describe the characteristics of the cytoplasm.
The cytoplasm is a jelly-like substance, primarily made of water and protein, where metabolic reactions occur.
What is the function of the cell surface membrane, and what is it made of?
The cell surface membrane is a partially permeable membrane, that controls substance movement (in & out) ; it is made of lipids and proteins.
Where does protein synthesis take place, and what are ribosomes made of?
Ribosomes are the sites of protein synthesis and are composed of RNA molecules and proteins.
Where does aerobic respiration occur, and what are the structural components of mitochondria?
Mitochondria are the sites of aerobic respiration, containing outer and inner membranes and a gel-like material called the matrix.
What is the role of the vacuole in plant cells, and how does it differ from animal cells?
The vacuole stores sugars, salts, and dissolved substances, maintaining turgor pressure, and is larger in plant cells compared to animal cells (little or no vacuole).
Describe the composition and function of the cell wall in plant cells
The cell wall is a rigid layer made of cellulose, giving plants shape and preventing bursting.
What do chloroplasts contain, and what is their role in plant cells?
Chloroplasts contain chlorophyll, a green pigment that traps sunlight for photosynthesis in plant cells.
Name the characteristics shared by living organisms using the acronym MRSGREN.
Movement, Reproduction, Sensitivity, Growth, Respiration, Excretion, Require Nutrition.
What are the characteristics of eukaryotic cells in terms of multicellularity, size, and organelles?
Eukaryotic cells can be both multicellular and unicellular, larger in size (10-100μm), and have membrane-bound organelles, including a nucleus. Examples: Animals, plants, fungi, protists.
Describe the characteristics of prokaryotic cells regarding multicellularity, size, and organelles.
Prokaryotic cells are unicellular, smaller in size (1-10μm), lack membrane-bound organelles, and have no nucleus (free-floating DNA). Examples: Bacteria, archaea.
What is the fundamental unit of life, and what is the source of all cells?
Cells are the basic structural unit of life, and all cells come from preexisting cells.
What are organelles, and what makes them specialized?
Organelles are cell structures specialized with specific functions.
What do cells collectively form, and what is the term for similar cells carrying out the same function?
Cells form tissues, and similar tissues carrying out the same function are grouped into organs.
Define organs and how systems are formed.
Organs are made from tissues carrying out body functions, and systems consist of interdependent parts.
