ultrastructure + function of organellses in cells Flashcards
What is the basic unit of life?
A cell
Cells are the fundamental building blocks of all living organisms.
What are the two types of cells?
- Prokaryotic cells
- Eukaryotic cells
Prokaryotic cells are single-celled and lack a nucleus, while eukaryotic cells are complex and have a nucleus.
Define prokaryotic cells.
Single-celled organisms that do not have a nucleus or membrane-bound organelles
Prokaryotic cells are simpler in structure than eukaryotic cells.
Define eukaryotic cells.
Cells that make up multi-cellular organisms and contain a nucleus and membrane-bound organelles
Eukaryotic cells include those found in plants and animals.
What is the approximate size range of eukaryotic cells?
10-100 um
Eukaryotic cells are generally larger than prokaryotic cells.
What allows the ultrastructure of eukaryotic cells to be observed?
Electron microscope
Electron microscopes provide higher resolution images than light microscopes.
What occurs in the cytoplasm of a cell?
Chemical reactions
The cytoplasm is the site where many cellular processes take place.
What separates the cell cytoplasm from the external environment?
Cell surface membrane or plasma membrane
This membrane regulates the movement of substances in and out of the cell.
What are organelles?
Different structures inside the cell cytoplasm
Organelles perform various functions necessary for cell survival.
True or False: Eukaryotic organisms have genetic information as linear chromosomes.
True
Eukaryotic cells contain their genetic material organized into chromosomes within the nucleus.
Fill in the blank: Eukaryotic organisms contain numerous _______.
specialised organelles
These organelles perform specific functions within the cell.
What is the site of aerobic respiration in an animal cell?
Mitochondrion
What regulates the transport of materials in and out of the cell?
Plasma membrane
What structure takes part in cell division and forms spindle fibres?
Centrioles
What contains genetic information and regulates metabolic cell activity?
Nucleus
What modifies and packages newly made proteins into vesicles?
Golgi apparatus
What transports materials around the cell or out of the cell?
Vesicle
What is the dense spherical structure inside the nucleus that produces ribosomes?
Nucleolus
What is the function of rough endoplasmic reticulum (ER)?
It synthesises and transports proteins.
What is the role of cytoplasm in an animal cell?
Where metabolic reactions take place.
What is responsible for protein synthesis when attached to the ER?
Ribosomes
What synthesises carbohydrates and lipids in an animal cell?
Smooth endoplasmic reticulum (ER)
What are lysosomes and what do they contain?
They are vesicles that contain hydrolytic enzymes.
What is the structure of the plasma membrane?
Composed of a phospholipid bilayer, with proteins embedded in the layer.
What is the function of the cytoplasm?
Maintains cell shape and stores chemicals needed for metabolic reactions.
What surrounds the nucleus and has nuclear pores?
Nuclear envelope
What does the nucleolus produce?
RNA and ribosomes.
What is the structure of the rough endoplasmic reticulum?
Network of membrane bound flattened sacs called cisternae studded with ribosomes.
What is the structure of the smooth endoplasmic reticulum?
Network of membrane bound flattened sacs called cisternae. No ribosomes.
What does the Golgi apparatus do with newly made proteins?
Receives, modifies, and packages them into vesicles.
What are vesicles?
Small spherical membrane bound sacs with fluid inside.
What is the function of transport vesicles?
Transport materials inside the cell.
What do secretory vesicles transport?
Proteins that are to be released from the cell to the cell surface membrane.
What do lysosomes do?
Break down waste material including old organelles.
Where does protein synthesis occur?
At the ribosomes.
What are lysosomes?
Small spherical membrane bound sacs containing hydrolytic enzymes.
What are ribosomes?
Tiny organelles attached to rough ER or free floating in the cell, consisting of two sub-units and not surrounded by a membrane.
What are mitochondria?
Organelles with two membranes; the inner membrane is highly folded to form cristae.
What is the function of mitochondria?
Site of the final stages of cellular respiration.
What are centrioles?
Small tubes of protein fibres that form spindle fibres during cell division.
What is exocytosis?
Process of vesicles fusing with plasma membrane and secreting contents.
What is one key function of animal cells?
To synthesise proteins for use inside the cell, for cell multiplication, and for secretion out of the cell.
Where are proteins synthesised in animal cells?
On ribosomes attached to rough endoplasmic reticulum.
What happens to newly synthesised proteins in the rough ER?
They are transported through the cisternae and packaged into vesicles.
What is the role of the Golgi apparatus?
To modify and package newly synthesised proteins into vesicles.
What do secretory vesicles do?
Transport proteins to the cell surface membrane for release.
What is the structure of a plant cell wall?
Made of cellulose forming a sieve-like network.
What is the function of chloroplasts?
Site of photosynthesis, trapping light energy to produce carbohydrates.
What is a vacuole?
A membrane-bound sac in the cytoplasm that contains cell sap.
What is the function of the vacuole?
Maintains turgor to ensure a rigid framework in the cell.
What is the tonoplast?
The partially permeable membrane of the vacuole.
What is an amyloplast?
A double membrane-bound sac containing starch granules.
What are plasmodesmata?
Microscopic channels which cross the cell walls of plant cells.
What are pits in plant cells?
Pores in the cell walls of the xylem.
