Notes:
Liquid waste is excretion or egestion.
Statement –
1. Is never a question
2. Prediction + explanation
3. May be true or false
4. If it is false, come up with a new hypothesis
Annotations are to be used with biological drawings when you don’t know the actual parts of the specimen being drawn.
Carolus Linnaeus
- Called father of taxonomy
- Developed the naming system binomial nomenclature
- Two word name (genus & species)
Problems in classifying organism
Species
- Species are always changing
Standardized naming
- Genus Species
- Latin or Greek
- Italic in print
- Capitalize genus but not species
- Underline when writing
Rules for naming
The international code for binomial nomenclature contains the rules for naming organism
We will learn about:
- Cell structure and function
- Mitochondrion
- Micro body
- Intercellular space
- nucleus
Learning outcomes:
1. You need to be able to explain that the basic unit of all living thing is a cell
2. Identify structure and state the function of the main organelles in the cell such as nucleus, nuclear membrane, chromatin, ER, ribosomes, Golgi apparatus, lysosomes, chloroplast, cell wall
3. Identify the main organelles from diagrams
4. Compare and contrast plant and animal cells
5. Explain how the structure of specialized cells is related to function
Cell theory
1. All living things are made up of cells
2. Cells are the smallest working units of all
living things
3. all cells come from pre existing cells through cell-division
Definition of a cell
1. A cell is the smallest unit that is capable of performing life functions
Examples of cells
1. Amoeba proteus
2. Plant stem
3. Bacteria
4. Nerve cell
5. Red blood cell
Two types of cells
1. Prokaryotic cell
i. Do not have organelles that is surrounded by membrane (specialized structures in cells)
ii. Few internal structures
iii. One celled organism
2. Eukaryotic cell
i. Contain organelles surrounded by membranes
ii. Most living organism e.g. plant, animals, fungi
Surrounding the cell
Cell wall
1. Most commonly found in plant cells and bacteria
2. Surrounds the cell membrane
3. Rigid structure maintains the shape supports and protect the cell
4. Permeable to small molecules and proteins only
5. The membrane is fully permeable
Cell membrane
1. Selectively/ partially permeable of a cell that controls movement of substance in and out of the cell
Nucleus
1. Contain chromatin that control cell activity
2. Chromatin contains DNA which is genetic material
3. DNA contain instruction for traits & characteristic and to carry out the cell’s function
4. Separated from cytoplasm by nuclear membrane
Cytoplasm
1. Gel like mixture
2. Surrounded by the cell membranes
3. Contains organelles
Mitochondria
1. Referred to as the ‘powerhouse’ of the cell
2. The food we eat is transformed into energy (ATP) for the cell in our bodies.
Endoplasmic reticulum
1. An interconnected network of tubes and vesicles
2. Synthesis of proteins, fats, steroid (cholesterol)
3. Transports materials around in the cell
4. Smooth type: lacks ribosomes
5. Rough type: ribosomes embedded in surface
Ribosomes
1. Each cells contains thousands
2. Make proteins
3. Found on endoplasmic reticulum & floating throughout the cell
Golgi bodies
1. Works closely with ER
2. Primary function is to process and package complex molecules such as protein and fats that are made if the cells
3. Brings this products to the surface of the cell where they can be secreted
4. Other secretions include hormones, antibodies and enzymes
Biology by Campbell Reece
Biology by Audisurk and Audisurk
Lysosome
1. Contain digestive enzymes
2. Digest excess or worn out organelles, food particles and engulf bacteria or viruses
3. Also help repair worn out plasma membrane
4. They also provide sugars, amino acids and bases which are the foundation of macromolecules
5. Cell breaks down if lysosomes explode
Vacuoles
1. Membrane-bound sacs for storage, digestion and waste removal
2. Central large vacuoles help plants maintain shape
3. Food vacuoles: formed by phagocytosis
4. Contractile vacuoles in fresh water protists: pimp excess water out of the cell
Chloroplast
1. Usually found in plant cells
2. Contains green chlorophyll
3. Where photosynthesis takes place
4. Converts light energy into chemical energy in glucose
Differences between plant and animal cells
Plant cell Animal cell
1.A central large 1.Multiple vacuoles
vacuole that are small
2.Contains chloroplast 2.No chloroplasts
3.Cell wall present 3.Cell wall absent
4.Regular shape 4.Does not have a
regular shape
Specialized cells
1. Red blood cells
2. Xylem vessel
3. Root hair cell
4. Intestinal cell
The red blood cell has a biconcave shape so that there is more surface area as a result more oxygen can be diffused in and out of the cell efficiently.
Stands for:
S.A. = surface area
Rbc: red blood cell
(this short forms are not supposed to be used in exam)
• Ms Tok: (I will be using red to write my comments, and yellow to highlight keywords) Dear ladies, good job!
Cell Structure and Function
Red Blood Cell
Register 28 - 36
(Shin Tien, Sherisse,
Sumana,
Swathi,
Hui Li,
Jingyi,
Yuxing,
Yamon,
Clarice)
* and there is a video
the link is here:http://www.youtube.com/watch?v=vEmsaXA-go0&feature=fvwrel Yes, it is cute, and meaningful.(This video is more relevant when we touch on the topic of transport in mammals. So do remember to revisit this link then.)
There is another YouTube
ENJOY;)
Structure:
• It is doughnut shaped (it is biconcave) (Please do not use the term “doughnut-shaped” for describing the red blood cell, especially in your exam (biconcave meaning that it curves inside on both surfaces) but (does not have a hole in it <--no need to say this, as this phrase is referring more towards using a doughnut as an analogy to describe the red blood cell). There is a slight depression on both surfaces of the cell). A RBC has a strange shape -- a biconcave disc that is round and flat, sort of like a shallow bowl, which increases the surface for gas exchange.
• An RBC has no nucleus. The nucleus is extruded from the cell as it matures.
• An RBC can change shape to a great extent, without breaking, as it squeezes single file through the capillaries. (Capillaries are minute blood vessels through which oxygen, nutrients and waste products are exchanged throughout the http://www.wisegeek.com/what-is-a-red-blood-cell.htmbody.) By not having a nucleus, it can change shape easily.
• An RBC contains hemoglobin, a molecule specially designed to hold oxygen. <--This is not quite the structure though, more of a function
Function:
- The rbc avoid using the short form “rbc” in your exams which is also known as erythrocytes contains hemoglobin that binds
easily with oxygen (and carbon dioxide) to transports it from the
lungs to all parts of the body.
- (The rbc has no nucleus to enable it to
have circular biconcave shape<--This is the structure) increases
the surface area to volume ratio of the cell.
- (As a result, more oxygen can diffuse into
and out of the cell efficiently<--This is the function)..
-This is also because more RBC can be compacted into the same amount of space, therefore, more oxygen can be transported.
- Red cells contain haemoglobin and it is the hemoglobin, which permits them to transport oxygen - Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cells their red color (and their name).
Source: http://www.medterms.com/script/main/art.asp?articlekey=5260
http://www.wisegeek.com/what-is-a-red-blood-cell.htm)
Source: http://science.howstuffworks.com/environmental/life/human-biology/blood1.htm
For the information regarding red blood cells below, we will revisit this when we go into transport in mammals
• In humans, mature red blood cells are oval and flexible biconcave disks. They lack a cell nucleus and most organelles to accommodate maximum space for hemoglobin. 2.4 million new erythrocytes are produced per second..
The cells develop in the bone marrow and circulate for about 100–120 days in the body before their components are recycled by macrophages each circulation takes about 20 seconds. Approximately a quarter of the cells in the human body are red blood cells. Red blood cells are also known as RBCs, red cells,[5] red blood corpuscles (an archaic term), hamates, elytroid cells or erythrocytes (from Greek erythros for "red" and kytos for "hollow", with cyte translated as "cell" in modern usage).
This website is also very useful if you want to learn more about blood cells: http://www.wisc-online.com/objects/ViewObject. aspx?ID=ap14604
Red blood cells are the most common cell in blood. They carry oxygen around the body, from the heart to the extremities. All of the bodies tissues are dependent upon oxygen from red blood cells – if the flow is cut off, the tissue dies. The scientific name for a red blood cell is “erythrocyte,” meaning “hollow red cell.” http://www.wisegeek.com/what-is-a-red-blood-cell.htm
Video - the Red Blood Cell Song
http://www.youtube.com/watch?v=bpGmKWS_wkk
Xylem Vessel
(Xylem Cells)
Register 10 - 18
• (Xylem is made up of thick secondary cell walls, often deposited unevenly in a coil-like pattern so that they may stretch. It consists of three different types of cells: Xylem parenchyma cells and xylem fiber cells, which simply provide structural support for the most important xylem cells, the treachery elements (TE).The TE are completely dead at maturity, and act like pipes to allow water and dissolved minerals to flow through them. There are two types of tracheary elements: vessel elements and tracheid. Though they have some structural differences, these two types function in the same manner. Dead at functional maturity, they have a completely passive role in the transport of water through the plant. Water is moved from the roots to the rest of the plant due to two factors: Root pressure, in which osmosis moves water from the soil into the roots, and transpirational pull, where water is lost by transpiration in the leaves and the resulting surface tension pulls water up the xylem.<--This lot of information will be covered in more detail in Year 3 biology module. To serve their function without collapsing, xylem tracheary elements must be stronger than ordinary cells. Therefore, a key feature of their structure is secondary cell wall thickenings. These thickenings form in distinctive patterns, frequently rings, to provide maximum structural support.
• Xylem vessels are a long straight chain made of tough long dead cells known as vessel elements. The cells are arranged end to end and the cell walls, which would normally surround the whole cell, dissolve wherever they are touching another cell wall. This makes a tube (because there is no blocking cell wall); sometimes the cells are just filled with holes rather than have no blocking cell-wall.
• They have lignified cell wall and a large central cavity. The vessel cells are also devoid of protoplasm. Vessel members are interconnected through perforations in their common walls. The presence of vessel is a characteristic feature of angiosperms The secondary walls of vessels are filled with lignin, a kind of hard glue
• This point is for enrichment now. Do note that this will be covered in Year 3 Biology. Xylem vessels work because of the transpiration stream. It is caused by the evaporation of water from the cells in the leaf to the atmosphere. This transpiration causes millions of tiny rings of cartilage to form in the cell wall of the leaf. The resulting surface tension causes pressure in the xylem that pulls the water from the roots and soil. This is called capillary action. A xylem cell can also continue to conduct water through the xylem after death, because its conductive properties are purely mechanical, created by the shape of the cell, rather than being biological in nature. Without xylem cells, a plant would have no vascular system. Vascular plants are able to be much more complex than their non-vascular counterparts, and they could be considered an evolutionary step up from nonvascular plants.
• This point is for enrichment now. Do note that this will be covered in JC level Biology. The least specialized plant cell is the parenchyma cell, which metabolizes and store food. Collenchyma and sclerenchyma cells help support the plant. Xylem cells conduct water while phloem conducts food. Epidermal cells cover the leaves, stems, and roots like a skin.
• Xylem are just made up from cell walls left from cells, making hollow tubes. The walls of these tubes are hydrophilic, so water attaches readily to them, helping it to climb on its way up the plant.
• http://wiki.answers.com/Q/What_feature_of_a_xylem_cell_helps_it_do_its_job#ixzz21Pr9RVHV
• http://www.youtube.com/watch?v=2YI_eE8Ivpo&feature=fvwrel
This following information is for enrichment now. Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. Tracheid are one of two types of tracheary elements, vessel elements being the other. All tracheary elements develop a thick lignified cell wall, and at maturity the protoplast has broken down and disappeared.[1] The presence of tracheary elements is the defining characteristic of vascular plants to differentiate them from non-vascular plants. Tracheid build varies by location.
The two major functions that tracheids may fulfill are
• Part of the transport system
• Structural support
In most cases, the prime function of tracheids is transporting water. They occur in vascular bundles throughout the non-woody parts of the vascular plant and provide water and minerals collected by the roots to leaves and other parts of the plant (stem, flowers, fruits etc.).
A good example of structural support is in softwoods where tracheids are the major cell type. Tracheids give softwood its strength.
Because tracheids have a much higher surface to volume ratio compared to vessel elements, they serve to hold water against gravity (by adhesion) when transpiration is not occurring. This is likely one mechanism that helps plants prevent air embolisms.
Root Hair Cells
Register 19 - 27
There are 5 organelles in the Root hair cell, containing nucleus ← Spelling mistake!!!, cytoplasm, plasma membrane, cell wall and vacuole. The root hair cell has a large surface area but it is a delicate structure formed at the top of the root to enable root hair coverage to be the same
The Root Hair Cells have a long and narrow protruding end which increases the surface area to volume ratio, enabling the root hair cells to absorb more water and mineral salts from the soil. Plants absorb water from the soil by osmosis ← We will be covering this very soon... (the process where by the water . Root hair cells adapted for this by having a large surface area to speed up osmosis.
The following point is more about the use of the absorbed water rather than the function of the root hair cell. The absorbed water is transported through the roots to the rest of the plant where it is used for different
purposes:
• It is a reactant used in photosynthesis
• It supports leaves and shoots by keeping the
cells rigid
• It cools the leaves by evaporation
• It transports dissolved minerals
http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/organism_energy/photosynthesisrev5.shtml
http://www.youtube.com/watch?v=MT8Iywvc6js
For the clip shown in this link, it talks about the process of diffusion and active transport in root hair cells. You ladies will be learning about the process of diffusion soon, but for active transport, not this year.
Intestinal Epithelial Cell
Register 1-9
*
An Intestinal Epithelial cell.
• Also known as Enterocytes.
• Found in the small and large intestine and the colon.
The epithelial cells which mature into absorptive epithelial cells that cover the villi. These are the cells that take up and deliver into blood virtually all nutrients from the diet.
Source: http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/anatomy.html
Uses:
• Ion uptake
• Water uptake
• Sugar uptake
• Peptide and amino acid uptake
• Lipid uptake
• Vitamin B12 uptake
• Reabsorption ← should be “reabsorption” of
unconjugated bile salts.
• Secretion of immunoglobulin
http://www.bio.davidson.edu/people/kabernd/BerndCV/Lab/EpithelialInfoWeb/index.html
The intestinal epithelium is the epithelium that covers the small and large intestine.
It is simple columnar ← meaning the shape is like stacks of rectangles. Note that this is not in your LSS Biology syllabus and nonciliated.
They primarily take part in the digestive system.
However, they are also a part of the immune system. The mammalian intestine is covered by a single layer of epithelial cells that is replaced every 4–5 days.
Epithelial cells in the small intestine are a type of brush border cell (covered in microvilli) that are joined together by tight junctions to form a polymer impermeable membrane(nothing) can enter This portion that is underlined is generally covered at JC / university level. These cells are covered in microvilli to increase their absorptive surface area ← better phrase to state is to “increase surface area tp vp;ume ratio”, thus making them more efficient.
The information below is way beyond your level. If you want, you can read them for interest. The ability of certain epithelial cells to use active-transport systems, as discussed above, enables them to absorb filtered material, such as glucose from the lumen of the intestine, which can then be circulated to the rest of the body. Cells are also able to endocytose other materials that are necessary for cell growth and signaling. For more information, see transcytosis.
Epithelial Cells
• Bound together in sheets of tissue called
epithelia.
• Held together by interactions such as tight
junctions, adherents, desmosomes, and gap
junctions.
• Epithelial cells line the major cavities of
the body.
• Epithelia can specialize to act as sensory
receptors. They form taste buds, line the
nose, and are in the ear. They are also
found in the eye.
• The skin is made of epithelial cells.
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