Cells Flashcards
What is a nucleus
Largest organelle in animal cell (usually spherical)
Contains genetic material or DNA
Present in all cells except mature xylem and red blood cell
Function of nucleus
Control all cell activities in the cell
What is a mitochondrion
Found in all plant and animal cells
Occurs in very large amounts. Especially abundant in more metabolically active cells like muscle and liver cells
Function of mitochondrion
Carries out cellular respiration to release energy for the cell
What is a chloroplast
Contains chlorophyll
Present in leaf cells and other green parts of plants and algae
Function of chloroplast
Site of photosynthesis
What is a cell wall
consists of cellulose fibres and is fully permeable
Function of cell wall
Provide mechanical support for the plant cell
What is the cell membrane
Partially permeable
Function of cell membrane
Separates and protects the cell from its surroundings
Controls the movement of substances in and out of the cell
What is the cytoplasm
Jelly-like medium
Function of cytoplasm
Site of all cellular activities and chemical reactions
What is the ribosome
Structure found as free ribosomes or attracted to structures in the cytoplasm
What is the large central vacuole
Fluid-filled sac surrounded by a single partially permeable membrane
Largest organelle in the mature plant cells as it occupies 80% of mature plant cells
Function of ribosome
Involved in the synthesis of protein
Function of large central vacuole
Contains cell sap which is a solution of sugars and dissolved minerals
What is the vacuole
Fluid-filled sac surrounded by a single membrane
Small and numerous in animal cells compared to plant cells
Function of vacuole
Stores food and water substances
What is division of labour at a unicellular level
Different parts of the cell perform different functions in a coordinated way for the cell to function efficiently
Division of labour at multicellular level
Sharing of different functions in an organism among its cells, tissues, organs and organ systems. Ensures smooth running and effective working of different parts of an organism as a whole
Division of labour beyond cellular level
Function effectively despite its larger and more complex organisation. Different cells, tissues, organs and organ systems have specialised features to carry out different functions
What is an organelle
Structure within a cell that performs a specific function
What is a cell
Basic structural and functional unit of life
What is a tissue
Group of cells with similar structures that perform a similar function
What is an organism
All the organ systems working together to support the life of an organism
What is an organ
Different tissues which work together to perform a specific function
What is an organ system
Several organs working as an organ system to perform body functions
Parts of a generalized bacterium cell
Plural: Bacteria
Ribosomes
Nucleoid region (Where genetic material is)
Genetic material
Cytoplasm
Flagellum (Some cells for movement)
Cell membrane
Cell wall (mixture of protein and sugar)
Capsule (may be slime capsule)
What does a bacterium cell lack
nucleus and other membrane bound organelles
How do bacteria reproduce
Asexually
Binary fission:
Cell elongates as DNA is replicated
Cell wall and plasma membrane begin to divide
Cross wall completely forms around divided DNA
Cell divides`
What are viruses
Smallest particles known, non-living
Replicate in cells of living organism
Cannot carry out living processes on their own
Contains a strand of genetic material (DNA or RNA) surrounded by a protein coat, capsid, for protection
No cytoplasm, nucleus, organelles or its own membrane. May have an outer membrane that is derived from the membrane from the host cell. May be helical, polyhedral or complex in shape. may vary
What is used to treat bacteria
Antibiotics which either kill the bacteria or prevent it from reproducing properly
How does a virus infect a cell
Forces the host cell to use its own resources (nutrients, oxygen and food) to reproduce many copies of the virus. When the host cell dies, it bursts to release other copies of the bacteria, which will go on to infect other healthy cells. Virus cannot be destroyed by antibiotics
