Chemistry/Biology Chapter 3 Basic Structure of a cell by https://padlet.com/ronaldoyee_161/gzgo5pot4d4i en-us 2016-10-03 05:40:38 UTC 2023-04-08 18:49:07 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Xmastree.png Cells ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/127781502
  • contain genetic programme to
    • construct cellular structures 
    • run cellular activities
    • reproduce
  • carry out basic functions that are important for 
    • survival
    • growth
    • responding to stimuli
    • self-regulation
    • reproduction
    • evolution
    • ]]>     2016-10-03 05:45:09 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/127781502     Difference between bacterial cell(Prokaryote) and human cell(Eukaryote) ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/127781775 Prokaryotic cell
    Eukaryotic cell
    Membrane-bound organelles refer to organelles that have a barrier surrounding it]]>     2016-10-03 05:50:06 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/127781775     Features of a human cell ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/127788821 Cell membrane: A membrane that separates the inside of the cell from the outside environment. It also function as a selectively-permeable barrier that allows appropriate substance into the cell and keeps inappropriate substance out of the cell. 
    Cytoplasm: A jelly-like substance to hold the organelles in the cell
    Nucleus
    Nuclear membrane
    Ribosome
    Rough endoplasmic reticulum
    Smooth endoplasmic reticulum
    Golgi body or apparatus
    Mitochondria: 
    Lysosome: A membrane-bound pouch that contains digestive enzymes that is used to break down cell components and substances.]]>     2016-10-03 06:53:15 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/127788821     Nucleus ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129407933 A region that contains genetic materials. It is also the cell's genetic control centre. Usually spherical or oval in shape, the nucleus is surrounded by the nuclear membrane, a double layer membrane that separates the nucleus from the cytoplasm. The nuclear membrane  contains nuclear pores, which regulate the passage of materials between the nucleus and the cytoplasm.
    The RER (rough endoplasmic reticulum) is attached to the outer nuclear membrane. The RER is continuous with the ribosomes
    Nucleolus is a noticeable structure in the nucleus. The nucleolus produce ribosomal ribonucleic acid and ribosomes (Ribonucleic acid help code, decode, regulate and express the genes. It copies information from the DNA and is transported out of the nucleus. DNA cannot leave the nucleus).]]>     2016-10-10 05:34:47 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129407933     Ribosomes ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129410359 A molecular machine that produce protein according to the instructions given by the nucleus. Ribosomes have no membrane bounding it]]> 2016-10-10 06:02:03 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129410359 Endoplasmic Reticulum ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129410573 A microscopic series of tunnels used in the transportation and storage of substances. 
    Rough endoplasmic reticulum and smooth endoplasmic reticulum is present .
    The main difference between the rough endoplasmic reticulum and smooth endoplasmic reticulum is that the rough endoplasmic reticulum have ribosomes attached to it.
    The quantity of endoplasmic reticulum in the cells depends on the function of the cell. 
    Smooth endoplasmic reticulum produce lipids and process toxins.
    Rough endoplasmic reticulum produce membranes and proteins]]>     2016-10-10 06:04:38 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129410573     Golgi apparatus ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129411435 It modifies, matures and packages the newly produced proteins from the rough endoplasmic reticulum.
    The modified proteins will pass through the Golgi stack and is transported to the other organelles or to the cell surface.]]>     2016-10-10 06:13:51 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129411435     Mitochondria ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129411966 A region where energy is obtained from food consumed. The energy is used to support cellular activities.]]> 2016-10-10 06:19:38 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129411966 Deoxyribonucleic Acid ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129412465 Contains the hereditary material in humans. 
    The DNA is made up of 2 strands twisted into a spiral that is formed by base pairs attached to a sugar-phosphate backbone
    A DNA strand is a chain of nucleotides (a compound with a nitrogenous base, a sugar molecule and a phosphate group)
    Four types of nitrogenous base exist. They are adenine, thymine, guanine and cytosine. Adenine pairs up with thymine and cytosine pairs up with guanine]]>     2016-10-10 06:24:59 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/129412465     What is a cell? ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/131369013 A cell consist of a plasma membrane, cytoplasm, nucleic acids and ribosomes]]> 2016-10-18 06:17:04 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/131369013 Difference between Nucleoid and Nucleus ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/131369430 Nucleus have a nucleus membrane separating the nucleus from the cytoplasm.]]> 2016-10-18 06:21:16 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/131369430 Genes ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132478811 A gene is a part of DNA that is translate into protein. It is a part of DNA. Human beings have 20,000 to 25,000 genes, contributing to 3% of our DNA.
    DNA molecules are tightly packed around histones (an alkaline protein) to make chromosomes ]]>     2016-10-22 06:41:49 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132478811     Chromosomes ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132478855 In human, the DNA molecules are packaged into 46 chromosomes which is 23 pairs.
    Chromosomes 1 to 22 are called autosomes (These chromosomes do not determine sex) whereas chromosome 23 is known as sex chromosome. Females have 2 X chromosomes whereas males have 1 X and 1 Y chromosomes
    Diploid cells have 2 of each type of chromosomes (Total of 46). Haploid cells have 1 of each type of chromosomes (Total of 23)]]>     2016-10-22 06:43:04 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132478855     Mendelian Genetic ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132479260 Traits are the characteristics of an individual. 
    Only some traits are heritable. The heritable traits are under the control of genes. 
    Genotype is the genetic makeup of an organism.
    Phenotype is an observable trait.
    The Mendelian principle applies to all eukaryotes. Since cross-breeding cannot be controlled in humans, it is difficult to study the inheritance of genetic traits.
    Thus, the pedigree analysis is used to analyse genetic traits in human. Pedigree analysis is the examination of the occurrence of a particular trait in a family of individuals who exhibit the trait.
    Mendel's first law, the principle of segregation states that a gene pair will split into two to form an allele. In other words, 2 allele form 1 gene. 1 allele is inherited from the mother and another 1 is inherited from the father, forming a gene.]]>     2016-10-22 06:57:06 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132479260     Dominant and Reccessive Allele ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132479903 A dominant allele is one that is the most prominent
    A recessive allele is the opposite of a dominant allele.
    A dominant allele is denoted as a capital letter and a recessive allele is denoted as a small letter. 
    If an individual has two dominant allele, he will have the dominant trait. 
    If he has one dominant allele and one recessive allele, he will have the dominant trait.
    If he has two recessive allele, he will have the recessive trait.
    Homozygous is the state of having two identical allele for a particular gene
    Heterozygous is the state of having two different allele for a particular gene]]>     2016-10-22 07:18:34 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132479903     Movement of substance across the cell membrane ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132908954 Diffusion
    • A spontaneous and passive process where molecules move from a region of high concentration to low concentration until it reach equilibrium. The driving force is the concentration gradient. 
    Osmosis
    • The movement of water through a semi-permeable membrane from a more dilute solution to a more concentrated solution
    Active Transport 
    • A process whereby a cell uses energy to move substance across its membrane against a concentration. i.e. from a region of low concentration to a region of high concentration.
    ]]>     2016-10-25 05:52:20 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/132908954     Microbes ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028131 Microbes, also known as micro-organisms are living things that are too small to be seen by the naked eyes. Some microbes will harm human being but some will help us. Types of microbes include bacteria, archae, fungi, protozoa, algae and viruses]]> 2016-10-29 09:18:46 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028131 Sources of microbial (or microbiological) contamination ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028212
  • Microbial can contaminate many things such as food and water
  • Food can be contaminated by microbial through food handlers (unhygienic practices such as touching food with dirty hands, sneezing or coughing onto the food) or through dirty utensils and plates. 
  • Microbial contamination can also take place indirectly when food handlers touch doors, tap or clothes contaminated by microbial and touch the food without washing their hands. 
  • Raw food contains high amount of microbial. When raw food comes into contact with cooked food, the microbial can spread to the cooked food.
  • Microbes present in soil and water can contaminate the plants,  which can lead to food contamination if the microbes on the plant is not removed before eating.
  • Faeces can contaminate water and plants (if the fertilisers used for the plants come from untreated sewage)
  • The air contains lots of bacteria which can land on food, contaminating them
    • ]]>     2016-10-29 09:22:54 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028212     Effects of microbial contamination ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028601
  • Microbes can spoil food.
  • Viruses, parasites and fungi contamination can lead to foodborne diseases in humans.
  • Mainly, the consumption of microbe will lead to food poisoning.
    • For example, Anthrax is a gram positive bacteria used in biological war (An act of war where harmful bacteria are deliberately released somewhere) Anthrax is very infectious and can infect humans through the skin or air.
    • Escherichia coli is a gram negative bacteria that commonly cause foodborne disease. People infected by Escherichia coli will experience bloody diarrhoea. The old and the young's kidney may fail which can lead to death. In September 2006, an outbreak occurred in USA due to the consumption of spinach contaminated with the bacteria
    • ]]>     2016-10-29 09:33:35 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028601     Prevention of microbiral contamination in food. ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028973 This can be prevented through good practice of food hygiene, including
    • hand washing (preferably using soap or ash sanitiser) before and during food preparation, especially after using the lavatory and after handling raw food or waste
    • not letting raw food and cooked food come into contact. 
    • not preparing food when sick. This can cause a foodborne disease when people eat the food. In crowded or unsanitary living conditions, an outbreak of the disease can happen
    ]]>     2016-10-29 09:44:36 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/134028973     Genes and allele ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/135998704 One gene consist of 2 allele. 
    Genes are found on chromosomes
    Each gene has a designated place on every chromosome, called a locus. ]]>     2016-11-08 05:40:19 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/135998704     Genetic Carrier ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/135999483 A heterozygote which possesses the recessive alleles may appear just as normal as the homozygous dominant genotype
    A heterozygous individual who possesses a "bad" recessive allele hidden from phenotypic expression by the dominant normal allele is called a carrier
    A person who inherited a recessive allele for a genetic disease but do not display any symptoms of the disease]]>     2016-11-08 05:56:23 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/135999483     Fungi ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139259728 Eucaryote. Acquire food by absorption. Reproduce both sexually and asexually. Example: Yeast (Unicellular)]]> 2016-11-22 05:33:09 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139259728 Protozoa ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139259793 All unicellular. Eucaryote. Live in water and soil. Reproduce both sexually and asexually. Example: Amoeba, Euglena, Paramecium. Movement by pseudopods, flagella or cilia]]> 2016-11-22 05:35:01 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139259793 Algae ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139259869 Photosynthetic eucaryotes. Reproduce sexually and asexually. Obtain food by diffusion. Unicellular, multicellular, forming colonies, filaments or even tissues. Photosynthesise and produce oxygen and carbohydrate]]> 2016-11-22 05:37:05 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139259869 Virus ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139260194 Cause a wide variety of disease
    Considered to be non-living because they cannot reporoduce or carry out metabolic activities outside a host cell. ]]>     2016-11-22 05:43:32 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/139260194     Ribonucleic acid ronaldoyee_161 https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/140404401 Can be found in both the cytoplasm and nucleus. Different types of RNA]]> 2016-11-29 05:30:47 UTC https://padlet.com/ronaldoyee_161/gzgo5pot4d4i/wish/140404401