CTR Tutorial BOOK - helpful PDF

Preview

Summary

helpful...

Description

Tutorial workbook 1014MSC Cells, Tissues & Regulation

Assessment

Due Date

Location

Weight/Marked out of

Health and Safety Induction Modules

22 July 2021 Prior to Week 1 lab

L@G

0%

Weekly Online Quiz

Monday each week starting from Week 2

L@G

25%/25

Lab Exam

3 September 2021

G16_4.29/L@G

15%/10

Research Encounter

3 September 2021

L@G

15%/15

End of Term Exam

12 September 2021 Sunday (9:00AM – 11.10 AM)

L@G

45%/90

Document References Human Anatomy & Physiology, Global Edition by Elaine N. Marieb, Katja Hoehn as our required textbook (ISBN 9781292261034).

Please bring this workbook to your tutorials to go over the questions and concepts. Make sure you answer all questions.

1014MSC; CTR (Intensive)

2

Module 1: Cells & Tissues Checklist a) Reviewed mini-lectures 1.1, 1.2, 1.3, 1.4, 1.5 & 1.6 b) Completed on-line quizzes c) Attended compulsory tutorial sessions d) Completed workbook tasks e) Completed reflection in workbook

1014MSC; CTR (Intensive)

3

Topics 1.1: Cell structure and function Read Chapter 3: Cells: The Living Units of the prescribed course textbook.

Cells are the fundamental structural and functional unit of life on Earth. Based on morphology, there are two types of cells in nature, prokaryotes and eukaryotes. We will examine these in details, placing emphasis on structure and function of the parts that make up these cells.

Prokaryotes 1. Bacteria non-photosynthetic and photosynthetic, including blue-green algae (cyanobacteria) 2. Archaea live in extreme environments e.g. halophiles; high salt environment, thermoacidophlies; hot, sulphur springs, pH25,000 reactions per second.



Each membrane phospholipid can travel the breadth of its organelle or cell in under a minute.



The hundreds of trillions of mitochondria inside you are replaced about every 10 days, for as long as you live.



The fluid plasma membrane’s composition is constantly changing.

1014MSC; CTR (Intensive)

7

Cellular Transport How do molecules move within the cell? The nucleus: The nuclear envelope contains nuclear pores. Messenger RNAs and ribosomes are synthesized in the nucleus and exported to the cytoplasm. Materials such as proteins needed in the nucleus are imported into the nucleus. This is an energy demanding process. The Endomembrane System: The endomembrane system is composed of the smooth and rough ER and the Golgi apparatus, and is the primary system for protein and lipid synthesis. Ions, ATP, amino acids, and other small molecules diffuse randomly throughout the cell, but the movement of proteins and other large molecules is energy demanding and tightly regulated. Proteins are packaged into vesicles when they move from the rough endoplasmic reticulum to the Golgi apparatus and from the Golgi apparatus to the cell surface. The rough endoplasmic reticulum and Golgi apparatus function as an integrated endomembrane system. Each protein that comes out of the Golgi apparatus has a molecular tag that places it in a particular type of transport vesicle. Each type of transport vesicle also has a tag that allows it to be transported to the correct destination. Proteins produced in a cell have distinctive molecular address labels, which allow proteins to be shipped to the compartments where they function. The cytoskeleton: The cytoskeleton is a complex network of fibres that helps maintain cell shape by providing structural support. The cytoskeleton is dynamic; it changes to alter the cell’s shape to transport materials in the cell or to move the cell itself. Interactions between cytoskeleton components can cause cell movements such as cell crawling, cytokinesis, and cytoplasmic streaming.

1014MSC; CTR (Intensive)

8

Topic 1.2: Cell division and protein synthesis DNA & RNA Structure      



DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are nucleic acids The basic building block of DNA and RNA are nucleotides Each nucleotide is made up of a base, sugar and a phosphate group There are five types of bases: adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U) Sugar can be deoxyribose or ribose DNA is the genetic material, consisting of genes (short segments of the DNA) o Located in the nucleus o Functions: passes genetic information to descendent cells & carries information for building proteins o DNA is a long, helical, double-stranded chain of nucleotides- or ‘double helix’ o Bases are A, G, C & T o Hydrogen bonds between the bases of nucleotides hold the double helix together like ‘rungs’ on a ladder; the sugar and phosphate group form the ‘ladder’ itself. o The base paring is specific: A & T and G & C o A & T and G & C are referred to as complementary bases RNA carries out the orders of DNA for making proteins o RNA is single stranded nucleotide containing the bases A, G, C & U. The thymine (T) is substituted with uracil (U). o The base paring is: A & U and G & C o 3 forms of RNAs: messenger RNA (mRNA), ribosomal RNA (rRNA) & transfer RNA (tRNA) o mRNA is made in the nucleus and shipped out into the cytosol, carrying information for protein synthesis

DNA Replication 

 

DNA replication is the process of making multiple copies of identical DNA in the parent cells in order to be packaged into descendent cells. In this way, identical genetic information is passed from the parents to descendants. DNA replication occurs during the interphase (S phase) time period of the cell cycle. DNA is separated and each strand serves as a template for forming a complementary strand. Base pairing rule specifies the correct positioning of nucleotides in the formation of the complementary strand. 2 DNA molecules are made from the old one: each formed with one ‘old’ and one ‘new’ strand.

Protein Synthesis General Steps: DNA →

Transcription

RNA →

Translation

Protein

DNA serves as the blueprint for making protein. A gene (short segment of DNA) specifies the coding sequence of amino acids that form a protein. The 4 nucleotide bases (A, G, T & C) of DNA serve as the “letters” of the genetic alphabet. Each sequence of 3 bases (triplet) acts like a “word” specifying one particular amino acid. Therefore, each triplet represents one amino acid. Variations in the arrangement of bases produces different types of “words”, specifying different types of amino acids. There are 20 types of amino acids. 1014MSC; CTR (Intensive)

9

In a gene, the bases:amino acid ratio is 3:1. For example, if a gene has 360 base pairs, it will produce a protein made up of 120 (360/3) amino acids. Exons describe the coding regions of genes that produce proteins, whereas introns are the non-coding segments. Introns separate the exons.

Transcription  Transcription describes the process whereby DNA’s information is encoded into RNA.  mRNA is the form of RNA which caries the information encoded by the DNA.  Transcription cannot begin until a transcription factor binds to the promoter region of a gene.  3 basic steps underlie transcription: o 1) Initiation: Transcription factors help the enzyme RNA polymerase to bind to the promoter region. RNA polymerase forcefully separates the two DNA strands and initiates mRNA synthesis at the starting point of the template strand (the strand of DNA used for coding). o 2) Elongation: As the RNA polymerase moves along the template strand, the mRNA transcript is made/elongated one base at a time. o 3) Termination: mRNA synthesis ends when the RNA polymerase reaches a special sequence on the DNA called the termination signal. The mRNA transcript now separates from the DNA. Translation  Translation describes the process whereby the information carried by mRNA is decoded to form a protein.  The genetic code specifies the sequence of bases in mRNA that are translated to form an amino acid sequence. A sequence of amino acids that form a protein is also called a polypeptide sequence.  The codon describes the 3-base sequence in mRNA that corresponds to the triplet in DNA.  Since there are 4 kinds of RNA nucleotides, there 43 (64) possible codons. 3/64 codons code ‘stop’ signals halting protein synthesis. The rest code for amino acids. Since there are only 20 amino acids, some are specified by more than one codon.

1014MSC; CTR (Intensive)

10

Topic 1.1: Cell structure and function 1. List any 4 key differences between prokaryotes and eukaryotes?

2. Describe the structure and function of the plasma membrane using a diagram.

3. What are some of the major structural and functional differences between rough ER and smooth ER?

1014MSC; CTR (Intensive)

11

4. Describe the structure and function of the nucleus.

5. Describe the structure and function of ribosomes.

6. Describe the cytoskeleton and list three different types of fibres.

1014MSC; CTR (Intensive)

12

7. Label the following diagram

A. B. C. D. N.

E. F. G. H. I. J. K. L. M.

1014MSC; CTR (Intensive)

13

Topic 1.2: Cell division and protein synthesis 1. Describe the differences between structure, location and function of DNA and RNA.

2. Describe the structure and function of chromatin.

3. In simple terms, differentiate between translation and transcription.

4. Describe the different stages of mitosis along with specific events in each phase.

1014MSC; CTR (Intensive)

14

1. Where is DNA stored in eukaryotic cells? a) Lysosome b) Nucleolus c) Nucleus d) Peroxisome

2. What type of molecule can pass directly through the plasma membrane phospholipid bilayer? a) Carbohydrates b) Lipids c) Proteins d) Water

3. Which two cellular structures are supported by microtubules? a) Chromatin and nucleus b) Cilia and flagella c) Flagella and chromatin d) Nucleus and ribosomes

4. Which of the following organelles is not part of the endomembrane transport system in a eukaryotic cell? a) Endoplasmic reticulum b) Golgi apparatus c) Mitochondria d) Nucleus

5. What is the cytosol? a) The cytoskeleton that supports the inside of the plasma membrane b) The fluid, the organelles and the inclusions found inside a cell c) The space between the cristae in mitochondria d) The viscous, semitransparent isotonic fluid of the cell in which other cytoplasmic elements are suspended

1014MSC; CTR (Intensive)

15

6. What nucleotide is substituted for uracil in RNA? a) Adenine b) Thymine c) Cytosine d) Guanine

7. What molecules does the smooth endoplasmic reticulum produce? a) Carbohydrates b) Lipids c) Proteins d) Sugars

8. The extracellular matrix exists in which space? a) Inside the cell in the cytosol b) Inside the nucleus c) Outside the cell in the extracellular fluid d) Outside the intracellular matrix of the mitochondria

1014MSC; CTR (Intensive)

16

Topics 1.3 - 1.6: Tissue types & Integumentary system Read Chapter 4: Tissue: The Living Fabric and Chapter 5: The Integumentary System (section 5.1-5.3 & 5.5-5.7) of the prescribed course textbook.

Cell diversity & Tissues The cell used to illustrate cell structure, cell organelles and cell function is ‘made-up’ for the purposes of illustration. Cells vary hugely in shape and function, but with no exceptions, all have:  a cell membrane  cell organelles &  cell cytoplasm which is different in content to the tissue fluid that surrounds the cell These are all conditions of life. All cells begin life with a nucleus, and with one or two exceptions, retain this nucleus through their lifespan. We have at least 200 easily recognizably different cell types. Many types have subdivisions, and in some, one cell type can “turn” into another, depending on changing needs or conditions. Each cell contains the entire component of human DNA, and therefore theoretically each cell could divide to form any other cell type. However, most cells once mature are “differentiated’ and cannot do this. Figure 3.1 (Marieb) illustrates various cell types and shows that the shape of the cell is adapted to that cells function: 

Cells that provide physical (or “structural”) connections, holding the body together, e.g. epithelial cells and bone forming cells



Cells that line tissues and define body compartments, e.g. tall box-like ciliated cells in the respiratory tract (the mucociliary escalator – what does this achieve?)



Cells that store nutrients, e.g. adipose (fat) cells



Cells that transport rapid electrical signals, nerve cells, which are far too small to see with the naked eye, but which may extend (much supported by other tissues), for a metre or so – where does this occur?



Cells that are far larger than most others and can contract with great force (single skeletal muscle cells may extend 30 cm or so)

While some of the cell types listed above can change shape, they all generally remain in the same position within the body, but we also have mobile cells that: 

transport oxygen; termed red blood cells (RBCs) or erythrocytes (more later)

 

wander about in tissues cleaning up debris - the macrophages swim hard in an attempt to fertilize an egg (the egg itself is wafted along the fallopian tubes, but cannot “self-propel”) - sperm

1014MSC; CTR (Intensive)

17

Tissues Marieb Chapter 4 covers material on tissues. The lectures selectively cover material deemed relevant for the course. Students are advised to refer to the lecture notes and slides for what is considered most important to this course, and what might require less attention. Epithelial Tissues – Covering/Lining From the lectures, you should be able to understand how epithelia are characterised by the following:     

Basement membrane (BM) Avascular (avascularity) Tight junctions Microvilli (often, but not all) High regeneration capacity, and reasons for it (and consequences with respect to cancer)

There are numerous subtypes; of these at least be able to describe:     

Simple vs Stratified Squamous: simple (e.g. capillaries, termed endothelium) vs stratified (e.g. epidermis; described in some detail subsequently). Cuboidal: not the most common, perhaps remember that they occur in the kidneys Columnar: important subdivision, take the GI tract and respiratory tube as examples, understand the difference between simple columnar and stratified columnar Transitional and Pseudostratified: HD level

Note that cell nuclei reflect cell shape, flattened in flattened squamous cells, elongated in a columnar cell. Epithelial Tissues – Glandular Inclusion of glandular tissue as epithelial (which refers to “covering”) is counterintuitive. However, glandular tissue derives embryonically from epithelia precursor cells and glandular cells are also found within the linings of either internal or external surfaces of the body, like all epithelial cells. Glandular cells generally produce and export a protein-containing aqueous solution (e.g. tears, sweat externally, or protein-derived hormones internally). Some produce lipidbased products (e.g. steroid hormones & sebum, the oily compound that is sent to the surface of the skin). Export of secretions to the outside of the body is termed exocrine, which includes secretion into the gut tube. Export into the internal tissues is termed endocrine. Here products (known as hormones) are generally picked up by blood and distributed throughout the body. Exo: external, Endo: internal

1014MSC; CTR (Intensive)

18

Endocrine glands/glandular tissue In some cases, specific endocrine glands exist, producing hormones that typically have profound effects on the body, e.g. testosterone from the testis, released in large amounts in pre-pubescent boys, and oestrogen from ovaries in girls. In other cases, cells scattered within another major tissue or organ release hormones (important examples include endocrine cells in kidney and heart tissues). In either case, the secretions are sent into the interstitium without the need of ducts, hence the alternative term: ductless glands. More on all this when the endocrine system is discussed later. Exocrine glands Or ducted glands, since secretions are sent via tubes to the exterior. The subdivisions within different tube arrangements need not be remembered in great detail; remember that ductal cells line the tubes, and that alveolar cells line the proximal “pockets” that are found in some glands. As you can see in fig 4.6, all possible combinations of ducts and alveolar sections seem to exist. The term alveolar is again met in the lungs, since it means “little bag” and we have millions of them to exchange gases – these respiratory alveoli, as they are called, are not glandular. There is one major unicellular gland, the goblet cell: describe the structure and function of this cell. Connective Tissues (CT) The name is self-descriptive, but these tissues can vary very widely in form and function. All derive from the same tissues embryonically (mesenchyme; we are unlikely to find time to discuss this further for the moment) The most important distinctions between epithelial and connective tissues is that epithelial function is defined by the cells that make up the tissue, and these cells are tightly bound to each other while the function of CT is almost always determined by what the cells produce, i.e. by their extracellular matrices, and the cells are usually well spaced, not in contact with each other. Obvious “connecting” examples include bone, cartilage, tendons & ligaments (know the difference between tendons & ligaments). Fat cells are also CT cells, but these insulate the body, protect it against bruising, and store energy rather than playing a “connecting” role. Some CTs are very vascular (blood itself is an example of a CT), and other CTs are almost completely avascular (like tendons, and it can make for slow repair when such tissues are damaged). Ground Substance Marieb p 147-148: the terminology is a little advanced for this course, but understand that most of the material that fills in the spaces between cells (apart from water) is produced by CT cells. This extracellular matrix is formed by protein/sugar molecules, along with protein fibres, and the matrix can vary between being very watery, to gel like and viscous, to exceptionally hard. 1014MSC; CTR (Intensive)

19

CT origins and types See fig 4.8 Marieb: this is a useful summary of the sources of the major CTs. All the cell types are illustrated in the lecture slides. We will not cover blood again here but remember its CT origins, the fact that it provides a watery connection between all tissues, and that it is obviously crucial to life. CT proper Largely composed of collagen fibres (of different sorts), some linked like very tough rope, some more loosely arranged. Know what fibrocytes do. Loose (areolar, adipose and reticular)  areolar is most common type, loose packing between cells, can act like a sponge and expands when filled with fluid (termed oedema; this is seen in the quick swelling around a sprained ankle, for example)  reticular, delicate mesh-works through which cells can readily pass (seen in lymph nodes)  adipose tissue, fat cells for fat storage Dense   

dense & regular (tough and fibrous, e...