1: Cell Structure & Function Flashcards
What are microns?
Microns are the measurement used to describe cells. They are written as 10 to the power of 6 or as um
What are cells?
All living things are made of cells. They are the basic building block of all biological matter
What is cell differentiation?
Cell differentiation is the process where a cell specialises to carry out a certain role
What is the structure of plasma membrane?
The plasma membrane is a bilayer mainly made up of lipids, within which many different proteins are embedded
What is the role of the plasma membrane?
The role of the plasma membrane is to separate the extracellular from the intracellular. However, for the cell to work the membrane must allow selective movement of molecules and ions in and out of the cell. This is done in a very controlled way with the help of many different specialised proteins. The cell membrane also allows for communication with other cells
What is the cytoplasm?
The cytoplasm is the contents of the cell, not including the nucleus
What is the cytosol?
The cytosol is a viscous fluid that makes up the cytoplasm of the cell
What is the role of the cytosol?
The cytosol is where ions and molecules are dissolved and protein molecules are suspended
What is the structure of the nucleus?
The nucleus is a large membrane bound structure made up of nucleoplasm contained within the nuclear envelope
What is the nuclear envelope?
The nuclear envelope is a bilayer membrane perforated by nuclear pores. Some molecules can move between the cytoplasm and nucleoplasm through these nuclear pores
What is the nucleolus?
The nucleolus is a dense area within the nucleus where special DNA that helps to produce ribosomal DNA is found and ribosomal sub-units are manufactured
What are cell organelles?
Cell organelles are sub cellular structures that have one or more specific jobs to perform within the cell
What are ribosomes?
Ribosomes are made up of two globular proteins and ribosomal RNA. Some ribosomes float free in the cytoplasm, others are attached to the endoplasmic reticulum. These two types of ribosome carry out slightly different roles
What is the role of the ribosomes?
The structures within the ribosome fit together to form a structure which when occupied by a piece of messenger RNA act together to synthesise new proteins in a process called translation
What is the role of a free ribosome?
A free ribosome makes soluble proteins that mainly function within the cytosol
What is the role of ribosomes attached to endoplasmic reticulum?
Ribosomes attached to endoplasmic reticulum synthesise proteins destined for incorporation into the cell membrane for export from the cell
What is the endoplasmic reticulum?
The endoplasmic reticulum is a system of interconnecting tubes and membranes enclosing fluid-filled cavities. There are two forms of endoplasmic reticulum: rough and smooth
What happens to proteins assembled on the ribosomes of the rough endoplasmic reticulum?
Rough endoplasmic reticulum has an external surface stubbed with ribosomes. The proteins assembled on these ribosomes enter the interior of the ER cisternae where they’re processed further before being release in vesicles to pass to the next structure: the Golgi apparatus . From there, the proteins travel to the cell membrane or out of the cell as exported proteins
Into ER- processed- vesicles- Golgi apparatus- cell membrane or exported out of the cell
What is the role of the smooth endoplasmic reticulum?
The smooth endoplasmic reticulum is responsible for the production of lipids such as phospholipids, steroid hormones and carbohydrates. It also has a role in detoxification
What is the Golgi apparatus?
The Golgi apparatus consists of stacked and flattened membranous sacs and lots of tiny membranous vesicles
What is the role of the Golgi apparatus?
The Golgi apparatus receives vesicles released from the rough ER on its cis face (facing the nucleus and ER). It modifies and concentrates the proteins and lipids. The various proteins are then tagged for delivery to a specific address, sorted and packaged into vesicles at the trans face (the shipping side of the golgi sack)
What is the role of the mitochondria?
The mitochondria is the power station of the cell with a double membrane structure with many complex enzyme systems located within the matrix on the inner membrane and inter membrane space. Enzymes break down complex molecules like glucose into CO2 and H20 by oxidative metabolism. This process releases energy which is used to manufacture high energy adenosine triphosphate
What is the role of enzymes?
Enzymes are a protein that act as a catalyst to bring about a specific biochemical reaction
What is adenosine triphosphate?
Adenosine triphosphate is considered cellular fuel which is used by the cell to drive all of its processes and mechanisms
What are intracellular vesicles?
Intracellular vesicles are found free within the cytoplasm and have important and varying roles including lysosomes and peroxisomes
What is the role of lysosomes?
Lysosomes contain hydrolytic enzymes that break down proteins, nuclei acids, guards and lipids. They are seen as an intracellular digestive system
What is the role of peroxisomes?
Peroxisomes contain enzymes that break down fatty acids and amino acids, creating hydrogen peroxide as a waste product which is broken down by catalase into water and oxygen
What is the role of proteosomes?
Proteosomes break down and recycle proteins for the cell
What is the role of the cytoskeleton?
The cytoskeleton supports ells and holds the nucleus and organelles in position
What is the cytoskeleton made up of?
It is made up of three types of proteins: microtubules, actin filaments and intermediate filaments
What are microtubules?
Microtubules are hollow tubes made up of tubulin sub-units
What is the role of microtubules?
Microtubules provide structure and support to the cell and are seen as intracellular scaffolding. They’re important in cell division and the movement of intracellular materials
What are actin filaments?
Actin filaments are small fibrils made up of actin subunits that make up bundles, sheets and networks within the cell
What is the role of actin filaments?
Actin filaments provide support for the cytoplasm and the plasma membrane, which is important in muscle
What is the role of intermediate filaments?
Intermediate filaments provide mechanical strengths to cells, particularly in the long processes of nerves
What are intermediate filaments?
Intermediate filaments are protein fibres
What are the roles of cells?
Cells work in groups to undertake different roles on behalf of the organism. Every cell has the genetic capability to undertake al roles. Cells contain organelles which carry out different functions within the cell
What is the cytoplasm made up of?
The cytoplasm is made up of cytoskeleton and intracellular organelles. Different types of cells have different ratios of the two components
What is the role of the nucleus
DNA is located in the nucleus where it is associated it’s proteins called histones to form chromosomes
