Notes, abstracts, papers, exams and problems of Biology

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frf

Classified in Biology

Written at on English with a size of 750 bytes.

THE  EAR: has three parts: outer ear:auricle and ear canal. Middle ear: eardrum, eustachian tube and chain of ossicles. Inner ear: semicircular canals and cochlea. THE EYE: its formed of three layers: retina, choroid and sclera. The aqueous humour, the iris, the crystalline lens, the vitreous humour and the anatomical blind spot. THE SKIN: krause's corpuscle, hair follicle, the pacinian corpuscle, the adipose cells, the rufini corpuscle, the sebaceous gland, arrector pili, sweat gland, meissner's corpuscle and merkel's corpuscle. There are three layers:  epidermis, dermis and hypodermis.
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Viruses: Structure, Function, and Evolution

Classified in Biology

Written at on English with a size of 8.16 KB.

Structural Components of Viruses

  • Capsid: Protein shell that encloses a viral genome; may be rod-shaped, polyhedral, or more complex in shape
  • Viral envelopes: Membrane that cloaks the capsid that in turn encloses a viral genome

Obligate Intracellular Parasites

Viruses can only reproduce within host cells because they lack metabolic enzymes, ribosomes, and other equipment for making proteins.

  • Identifying host cells: "Lock and key" fit between proteins on the outside of the virus and specific receptor molecules on the host's surface (which originally evolved for functions that benefit the host).

Bacterial Defenses Against Phages

While phages have the potential to wipe out a bacterial colony in just hours, bacteria have defenses against phages:

  • Natural
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What is the time of the pet

Classified in Biology

Written at on English with a size of 2.85 KB.

Molecular biology is the science that studies the structure, function and
other aspects of nucleic acids . All the genetic information is passed from parents to children is in DNA. 
Genetic code is the 'dictionary' that matches the language of nucleotides
in the mRNA with the language of amino acids in proteins. It is organised in groups of 3 bases called codons . 
Properties of genetic code : It is organized in triplets : eacch amino acid is derermined by 3 nuclotides 
 It is universal, because all known organisms use it.
It is unidirectional because in translation mRNA is always read in the same
direction   It is ambiguous because each triplet have the same amino acid    
A mutation is a change in DNA which usually has effects on the expression
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jbjkjk

Classified in Biology

Written at on English with a size of 1.41 KB.

FOOD: A..BALANCED..diet contains, as from.UNDERNUTRITION (desnutricion)..A varied diet is the best, adequate..INTAKE(consumo)..Of all the essential nutri, vitamins and... MINERALS.., source of ..ENERGY.., ..STARCHES(almidon)..And complex polysaccharides, they contain more..CELLULOSE., the component..AMINO ACIDS..Of protein, digested and ..ABSORBED..Is found in meat, fish and.. PULSES(legumbres)..(beans,peas..), they provide..INSULATION(aislamiento).. Under the skin,..PROTECT..Major organs from trauma, ..FLAVOUR(sabor)..,increase palatability, only small...AMOUNTS(cantidades).., ...FISH..And plant oils, they can be.. STORED(almacenado)..In the liver, ..LOST(perdido)..From de body, ..RIVOFLAVIN..And nicotinic acid. ...CEREALS..(wheat,rye), ..
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Evolutionary Theories and Ecological Concepts: A Comprehensive Guide

Classified in Biology

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Evolutionary Theories

Punctuated Equilibrium vs. Neo-Darwinism vs. Neutralism

  • All three theories propose evolutionary change.
  • Punctuated Equilibrium: Evolutionary changes occur rapidly and abruptly.
  • Neo-Darwinism: Evolutionary changes occur gradually over time.
  • Neutralism: Most mutations have no effect on natural selection.

Barriers to Genetic Isolation

  • Geographical
  • Sexual
  • Physiological
  • Chromosomal
  • Ethological

Ecological Concepts

Abiotic and Biotic Factors

  • Abiotic Factors: Non-living factors that affect ecosystems (e.g., temperature, pH, wind)
  • Biotic Factors: Living components that affect ecosystems (e.g., disease, predation, competition)

Biomass

- Total dry weight of organic matter in organisms or ecosystems. - Includes carbohydrates, proteins, etc.

Ecosystems

... Continue reading "Evolutionary Theories and Ecological Concepts: A Comprehensive Guide" »
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biologia

Classified in Biology

Written at on English with a size of 1.55 KB.

1. Atom- molecule- organelle- cell structure- tissues- organ- system

Inorganic- Water chemical reactions take place. Minerals regulate cell functions.

Organic- Carbohydrates energy. Proteins catalyze chemical reactions. Nucleic acids DNA. Lipids structural role, energy and regulate proceses.

2.Cell Discovery 1655 Robert hook. 1838 Cell Theory Schleiden + Schwann. Cell theory states that cells are the structural, functional and reproductive units of living beings.

Prokaryotic- Bacteria.   Eukaryotic- Animal, Plant.  

Endosymbiotic model. 1- Aerobic bacteria- Mitochondria.   2- Photosynthetic bacteria- chloroplast. (2n) Diploid= 46 chr. (n) haploid= 23 chr 

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Digestive and Respiratory Systems: A Comprehensive Guide

Classified in Biology

Written at on English with a size of 4.08 KB.

The Digestive System

The digestive system is responsible for the ingestion, digestion, absorption, and elimination of food. It transforms food into nutrients through three main processes:

  1. Mechanical Digestion: Chewing, grinding, crushing, and mixing of food to break it down into smaller pieces.
  2. Chemical Digestion: Digestive juices break down macromolecules in food into smaller molecules that can be absorbed.
  3. Absorption: Nutrients are absorbed into the bloodstream and transported to cells throughout the body.

Ingestion

Ingestion begins when food enters the mouth. Key steps include:

  • Mastication (Chewing): Teeth tear and break food into smaller pieces.
  • Salivation: Saliva mixes with food, forming a bolus and aiding in swallowing.
  • Swallowing: The tongue
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Carbon monoxide along with oxygen a person feel suffocated because a) carbon monoxide reacts with oxygen b)lungs are are affected by carbon dioxide c)haemoglobin combines more rapidly with carbon monoxide than oxygen

Classified in Biology

Written at on English with a size of 2.07 KB.

NICOTINE: *afects the brain, it is a simulant, which means that it make you feel more active and alert. *makes heart rate and blood presure increase, which leads to heart desease. *it is an addictive, it is very hard to do without it.


TAR: *tar cigarette smoke is absorbed by some of the cells in the lungs, specially bronchi and bronchides. -bronchi and bronchides: normally this cells forma thin protective layer but tar makes them divide and build up into a thiker layer, this leads to cancer. *it is an irritant: it inflam the linings respiratory passages causinf chinoic bronchitic. *damages celia and causes extra mocus, bacteria breed in the mocus is made, this cause infections. * people start caughing to remove the mocus, the constant caughing
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Inorganic and Organic Biomolecules: Essential Components of Living and Non-living Things

Classified in Biology

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Inorganic biomolecules

Essential for non-living things.

  • Water: The most abundant substance found in living things. It makes up about 65% of the human body.
  • Mineral salts: Substances that can be found in living things in the form of dissolved ions, such as sodium ion.

Organic biomolecules

Unique to living things. Structures made up of carbon.

  • Carbohydrates: Made of carbon and water.
  • Lipids: Fats, phospholipids, and cholesterol.
  • Proteins: Chains of amino acids.
  • Nucleic acids: Groups of nucleotides.

The cell: Functions

  • Structural
  • Functional
  • Basic
  • Biological

Prokaryotic cell

  • No nucleus
  • Organelles: Ribosomes
  • Bacteria are prokaryotes
  • Membranes: Cell membrane, cell wall, and bacterial capsule (not always)
  • Flagella and Fimbriae

Eukaryotic cell

  • Nucleus
  • Cell membrane: two
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Cell Structures and Functions

Classified in Biology

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Metre: mm = 10-3, hm = 10-6, nm = 10-9

Plasma Membrane

The plasma membrane is partially permeable and contains the exchange of materials.

Chromatin

Chromatin is a mass of chromosomes during nuclear division, which is the material of which chromosomes are made.

Nucleolus

The nucleolus is a small structure, one or more inside the nucleus. Its function is to manufacture ribosomes.

Protoplasm

Protoplasm refers to all the living material inside the cell.

Cytoplasm

Cytoplasm refers to the contents of a cell excluding the nucleus.

Mitochondrion

The mitochondrion is the organelle in eukaryotes where aerobic respiration takes place.

Cell Wall

The cell wall gives the cell a definite shape and prevents the cell from bursting when water enters by osmosis.

Vacuoles

Vacuoles... Continue reading "Cell Structures and Functions" »

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