- Module 2.1.1 Flashcards
What are the components and role of the cell membrane?
It is the boundary of the cell.
Made of a phospholipid bi layer.
Controls exocytosis and endocytosis.
Selectively permeable.
Fragile.
What are the components and roles of the nucleus?
Controls DNA and therefore synthesis of proteins. DNA controls metabolic activity of the cell bc many of the proteins made are enzymes necessary for metabolism.
Contained within a double membrane called the nuclear envelope, protects the DNA from damage in the cytoplasm. Envelope contains gaps called nuclear pores allowing molecules to move in and out.
Usually easiest organelle to see under a microscope.
Usually one per cell.
DNA in nucleus associates with proteins called histones to form chromatin.
Chromatin coils and condenses to form chromosomes, only become visible when a cell is preparing to divide.
What is the structure and function of the nucleolus?
Area of the nucleus responsible for producing ribosomes.
Composed of proteins and RNA.
RNA is used to produce ribosomal RNA (rRNA) which is combined with proteins to form ribosomes.
What is the structure of the endoplasmic reticulum?
Network of membranes forming flattened sacs called cisternae.
Connect to the outer nuclear membrane.
What is the structure and function of the smooth ER?
No ribosomes.
Involved in lipid (cholesterol and steroid hormones) and carbohydrate synthesis and storage.
What is the structure and function of the rough ER?
Ribosomes bound to the surface.
Synthesis and transport of proteins.
What is the structure and function of the golgi apparatus?
Similar structure to smooth ER.
Compact structure of cisternae.
Looks like a stack of plates.
Stores, modifies and packages proteins into vesicles (secretory vesicles or lysosomes).
Molecules transported to and from the golgi by vesicles.
What is the structure and function of the mitochondria?
2-5 micrometers long.
Cellular respiration occurs here to release energy for the cell to use.
Double membrane, inside of which is highly folded and forms cristae.
In the centre of the mitochondria is a fluid called the matrix.
Has it’s own strand of DNA (mtDNA) and contains ribosomes.
Can produce their own enzymes and reproduce themselves.
What is the structure and function of the ribosomes?
20nm diameter.
Site of protein synthesis.
Found attached to rough ER or floating free in cytoplasm.
Constructed of RNA molecules produced in the nucleolus.
Combined of two subunits - a small and a large one that combine once they leave the nucleus.
Not surrounded by a membrane.
Mitochondria and chloroplasts contain ribosomes.
What is the structure and function of a vesicle?
They are membranous sacs with storage and transport roles.
Single membrane with fluid inside
Used to transport materials inside the cell
What is the structure and function of a lysosome?
Specialised type of vesicle that contains hydrolytic enzymes.
Break down waste material in the cell, including old organelles and pathogens ingested by phagocytic cells.
Play an important role in apoptosis.
What are the structures of cilia and flagella?
Extensions from some cells, provide motility.
Each cilium contains 2 microtubules surrounded by 9 pairs of microtubules arranged like a wheel (9+2 arrangement)
What is the function of cilia?
Hair-like
Used to move substances outside human cells
Can be stationary (nose) or mobile (oviduct or trachea).
Mobile cilia beat in a rhythmical manner which creates a current.
What is the function of flagella?
Whip like extensions.
Found on sperm cells.
Sometimes used as a sensory organelle detecting chemical changes in the cell’s environment.
What is the structure and function of chloroplasts?
4-10 micrometers long (large)
Double membrane structure
Enclosed fluid = stroma
Internal network of membranes that form flattened sacs called thykaloids.
Several thykaloids stacked togther = grana
Grana are joined by membranes called lamellae
Grana contain chlorophyll
Starch present as starch grains.
Have their own ribosomes and are able to produce their own proteins
Internal membranes give the large SA needed for enzymes, proteins and pigment molecules needed for photosynthesis.
What is the structure and function of the cell wall?
Found in plants, bacterial and fungal cells.
Contents of cell press against cell wall
Rigid, protective barrier
Outside cell membrane
Freely permeable
Made of cellulose in plants and chitin in fungi.
Contain gaps called plasmodesmata, allow for the movement of substances between cells
What is the structure and function of vacuoles?
Large central vacuole usually in plant cells
Many smaller vacuoles in animals, but not permanent
Bound by the tonoplast membrane
Storage container for water, food, enzymes, wastes, pigments etc.
What is the structure and function of centrioles?
Made up of microtubules.
Help in cell division by migrating to opposite ends of the cell (organisation of spindle in animal cells)