Cell Structure Flashcards
What is the nucleus for?
contains genetic info in DNA molecules.
DNA directs the synthesis of all proteins needed by the cell.
The nucleus is the biggest single organelle.
Contains DNA inside a double membrane.
Whats the nucleolus for?
place in the nucleus responsible for producing ribosomes.
Composed of proteins and RNA.
Whats the Nuclear envelope?
Surrounds the nucleus.
contains DNA within its double membrane, protects DNA from damage within the cytoplasm.
Contains nuclear pores, allow molecules to move in and out of the nucleus.
Role of the DNA?
inside the nucleus.
directs the synthesis of all proteins required by the cell.
controls metabolic activities of the cell.
Too large to leave the nucleus due to nuclear pores.
Transcribed into smaller RNA molecules in the nucleolus.
What are Chromatin?
DNA associates with proteins called histones to form a complex called chromatin.
Chromatin coils and condenses to form chromosomes.
RNA?
Produced as a product of DNA known as ribosomal RNA, small enough to pass through the nuclear pores.
RNA is combined with proteins to form the ribosomes needed for protein synthesis.
Mitochondria?
Has a double membrane, inner is highly folded to form structures called cristae and the fluid interior is called a matrix.
takes ADP,converts chemical energy in glucose into ATP via aerobic respiration.
What are vesicles?
vesicles are membranous sacs that have storage and transport roles.
They consists simply of a single membrane with fluid inside.
Vesicles transport material inside a cell.
What are lysosomes?
Lysosomes are special forms of vesicles that contain hydrolytic enzymes that break down waste materials in cells like old organelles.
They are responsible for breaking down pathogens ingested by the phagocytic cells.
They play an important role in programmed cell death or apoptosis.
What is the cytoskeleton?
its a network of fibres necessary for shape and stability of a cell.
What are microfilaments?
part of the cytoskeleton.
contractile fibres formed from a protein called actin.
Responsible for cell movement and cell contraction during cytokinesis.
What are microtubules?
part of the cytoskeleton.
globular tubulin proteins polymerised to form tubes, form a scaffold like structure to determine cell shape.
acts as tracks for movement in the cell like vesicles around the cell.
intermediate fibres?
gives mechanical strength to cells and help to maintain their integrity.
What are flagella?
used primarily to enable cells motility.
in some cells they are used as a sensory organ detecting chemical changes in a cell environment.
ribosomes?
can be free floating in the cytoplasm or attached to endoplasmic reticulum,forming rough endoplasmic reticulum.
Constructed of RNA.
Site if protein synthesis.
contained inside mitochondria and chloroplasts.
