1: Cell Structure & Function

Question 1

What are microns?

Answer 1

Microns are the measurement used to describe cells. They are written as 10 to the power of 6 or as um

Question 2

What are cells?

Answer 2

All living things are made of cells. They are the basic building block of all biological matter

Question 3

What is cell differentiation?

Answer 3

Cell differentiation is the process where a cell specialises to carry out a certain role

Question 4

What is the structure of plasma membrane?

Answer 4

The plasma membrane is a bilayer mainly made up of lipids, within which many different proteins are embedded

Question 5

What is the role of the plasma membrane?

Answer 5

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

Question 6

What is the cytoplasm?

Answer 6

The cytoplasm is the contents of the cell, not including the nucleus

Question 7

What is the cytosol?

Answer 7

The cytosol is a viscous fluid that makes up the cytoplasm of the cell

Question 8

What is the role of the cytosol?

Answer 8

The cytosol is where ions and molecules are dissolved and protein molecules are suspended

Question 9

What is the structure of the nucleus?

Answer 9

The nucleus is a large membrane bound structure made up of nucleoplasm contained within the nuclear envelope

Question 10

What is the nuclear envelope?

Answer 10

The nuclear envelope is a bilayer membrane perforated by nuclear pores. Some molecules can move between the cytoplasm and nucleoplasm through these nuclear pores

Question 11

What is the nucleolus?

Answer 11

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

Question 12

What are cell organelles?

Answer 12

Cell organelles are sub cellular structures that have one or more specific jobs to perform within the cell

Question 13

What are ribosomes?

Answer 13

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

Question 14

What is the role of the ribosomes?

Answer 14

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

Question 15

What is the role of a free ribosome?

Answer 15

A free ribosome makes soluble proteins that mainly function within the cytosol

Question 16

What is the role of ribosomes attached to endoplasmic reticulum?

Answer 16

Ribosomes attached to endoplasmic reticulum synthesise proteins destined for incorporation into the cell membrane for export from the cell

Question 17

What is the endoplasmic reticulum?

Answer 17

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

Question 18

What happens to proteins assembled on the ribosomes of the rough endoplasmic reticulum?

Answer 18

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

Question 19

What is the role of the smooth endoplasmic reticulum?

Answer 19

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

Question 20

What is the Golgi apparatus?

Answer 20

The Golgi apparatus consists of stacked and flattened membranous sacs and lots of tiny membranous vesicles

Question 21

What is the role of the Golgi apparatus?

Answer 21

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)

Question 22

What is the role of the mitochondria?

Answer 22

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

Question 23

What is the role of enzymes?

Answer 23

Enzymes are a protein that act as a catalyst to bring about a specific biochemical reaction

Question 24

What is adenosine triphosphate?

Answer 24

Adenosine triphosphate is considered cellular fuel which is used by the cell to drive all of its processes and mechanisms

Question 25

What are intracellular vesicles?

Answer 25

Intracellular vesicles are found free within the cytoplasm and have important and varying roles including lysosomes and peroxisomes

Question 26

What is the role of lysosomes?

Answer 26

Lysosomes contain hydrolytic enzymes that break down proteins, nuclei acids, guards and lipids. They are seen as an intracellular digestive system

Question 27

What is the role of peroxisomes?

Answer 27

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

Question 28

What is the role of proteosomes?

Answer 28

Proteosomes break down and recycle proteins for the cell

Question 29

What is the role of the cytoskeleton?

Answer 29

The cytoskeleton supports ells and holds the nucleus and organelles in position

Question 30

What is the cytoskeleton made up of?

Answer 30

It is made up of three types of proteins: microtubules, actin filaments and intermediate filaments

Question 31

What are microtubules?

Answer 31

Microtubules are hollow tubes made up of tubulin sub-units

Question 32

What is the role of microtubules?

Answer 32

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

Question 33

What are actin filaments?

Answer 33

Actin filaments are small fibrils made up of actin subunits that make up bundles, sheets and networks within the cell

Question 34

What is the role of actin filaments?

Answer 34

Actin filaments provide support for the cytoplasm and the plasma membrane, which is important in muscle

Question 35

What is the role of intermediate filaments?

Answer 35

Intermediate filaments provide mechanical strengths to cells, particularly in the long processes of nerves

Question 36

What are intermediate filaments?

Answer 36

Intermediate filaments are protein fibres

Question 37

What are the roles of cells?

Answer 37

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

Question 38

What is the cytoplasm made up of?

Answer 38

The cytoplasm is made up of cytoskeleton and intracellular organelles. Different types of cells have different ratios of the two components

Question 39

What is the role of the nucleus

Answer 39

DNA is located in the nucleus where it is associated it’s proteins called histones to form chromosomes