2.4/5 Cell Ultrastucture Flashcards
microfilaments
Made from protein actin
Responsible for movement of the cell and cytoplasm during cytokinesis
Microtubules
Globular protein tubulin
Polymerise to form tubes that determine the shape of the cell
Act as tracks for organelles
Intermediate fibres
Gives strength to cells and helps maintain integrity
Name all the structures in the nucleus
Double nuclear envelope
Nuclear pores
Nucleolus
Chromatin
Double nuclear envelope
Double membrane which compartmentalises the nucleus and prevents damage.
Protects DNA
Nuclear pores
Allows molecules to enter and leave the cell
Nucleolus
Site of ribosome production composed of RNA and proteins
Chromatin
Contains the genetic code which controls the activity of the cell
Function of the nucleus
Controls all activity of the cell
Where genetic code is stored and replicated
Nucleus is attached to rough ER so the mRNA can easily get to ribosomes
Rough endoplasmic reticulum
Stacks of membrane bound fluid sacs called cisternae
Covered ribosomes
Interconnected system of flattered sacs
Site of protein synthesis
Smooth endoplasmic reticulum
No ribosomes
System of interconnected tubes
responsible for carbohydrate and lipids synthesis
Flattered sacs called cisterne
Ribosomes
2 subunit organelle Made from RNA and protein No membrane Where protein is made They assemble amino acids into protein chains using mRNA
Mitochondria
Oval shaped . Double membrane
Inner membrane is folded - cristae ( increase surface area)
Soulution inside is called matrix - contains enzymes for respiration
Mitochondrial DNA - small amounts of DNA enable mitochondrion to reproduce and create enzymes
Golgi apparatus
Stacks of flattened , membrane bound sacs - cisterne
Allows internal transport
Receives protein from the RER
Modifies and processes molecules , by adding other molecules such as lipids and carbohydrates and packages them into vesicles
Makes lysosomes , lipid synthesis
Lysosomes
Spherical sacs surrounded by a single membrane
Contain powerful hydrolytic digestive enzymes- lysozymes
Role is to break down worn out components of other cells or digest invading cells
Centrioles
Component of the cytoskeleton composed of many microtubules
Small hollow cylinders in pairs next to the nucleus in animal cells
Each centriole contain a ring of 9 microtubules ( 9+2 formation) - arrangement allows movement
Makes a copy of itself during cell division and the helps to form the spindle in cell division
Hair like extensions that protrude form some animal cells
Sensory function.
Flagella
Similar to cilia but longer
Protrude from the cell curvaceous and are surrounded by plasma membrane
Like cilia they have a 9+2 arrangement
Whip like , enables a cells mobility. Microtubules contract to make the flagellum move
Chloroplasts
Double membrane which encloses the Stroma
Stroma contains : starch grains, lipid stores , DNA , RNA , ribosomes
Series of membrane bound flattened sacs called thylakoids in the Stroma . Thylakoids stacked together are called grana. Grana are linked by lamellae. The grana contain chlorophyll
Cell plasma membrane
Membrane found on the surface of animal cells and inside the cell wall of plant and prokaryotic cells
A phospholipid bilayer
Composed of proteins and lipids
Regulates the movement of stub stances into and out of the cell
Contains receptor molecules which allows it to respond to chemicals like hormones
Large permanent vacuole
Single membrane
Sores cell sap
Selectively permeable barrier
Supports herbaceous plants by making cells turgid
Sugars and amino acids act as a temporary food store
Cellulose cell wall
Cell wall is fully permeable to substances
Thin layer called middle lamella marks the boundary between adjacent cell wall
Gives mechanical strength and support
Contents of the cell can push against the cell wall
importance of the cytoskeleton
Aids transport vesicles within cells due to microtubules Provides scaffolding for cell Movement of chromosomes Cytokines Movement of cilia or flagella
Structure in animal cells that are not present in plants
Centriole + lysosomes
How do the organelles work together to release protein molecules from the cell
mRNA transcribes the genetic code for the proteins from the nucleus
RER or ribosomes is the site of protein synthesis where the genetic code is translated
Protein is packaged into a vehicle and transported to the Golgi
Protein is then modified
Vesicles travels to the cell surface membrane where it fuses by exocytosis out of the cell
Functions and flagella and cilia
Enables movement of cells by moving liquid past the cell
E.g sperm
Name a stage during the secretion of a protein that requires energy
Transport of vesicles to the cell surface membrane
Exocytosis
