Notes, abstracts, papers, exams and problems of Biology

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Muscles, tissue, joints, bone

Classified in Biology

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Joints are where two bones meet they form a joint.It may be a fixed joint as in the junction of the hip girdle and the vertebral column or a moveable joint as in the knee.Two important types of moveable joint are the ball and socket joints of the hip and the shoulder and the hinge joints of the elbow and knee.The balla ns socket allows movement forwards,backwards and sideways,while a hinge joint allows movement in only one direction.Where the surfaces of the bones in a jointrub over each other,they are covered with smooth cartilage wich reduces the friction between them.Friction is also reduced by a thin layer of a fluid called synovial fluid. Muscle:there are three main types of muscle.Skeletal muscle(or striated,or voluntary muscle).Smooth
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First cells and how they obtained energy

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Active transport is the movement of substances Across cell-membranes against a concentration gradient, from a region of low to A region of high concentration using energy from ATP.

Carrier mediated active transport

Carrier mediated active transport requires both energy (ATP) and the assistance of a transport protein, called pump.

Each pump only transports particular substances, so cells Can control what is absorbed and what is expelled. Pumps work in a specific Direction –the substance can only enter the

pump on one side and can only exit on the other side. Energy Is used to “pump” molecules across cell membranes against their concentration Gradients.

Vesicular active transport

Vesicular active transport is an energy-requiring Mechanism whereby... Continue reading "First cells and how they obtained energy" »


Posted by Kjay and classified in Biology

Written at on English with a size of 1.57 KB.

9 Animal Phyla- Porifera, sessile but motile sperm, some specialized cells but no tissues, endoderm and mesoderm only,asymmetrical,EX Sponges, (filter bacteria and other contaminants from water, forms coral reefs). Cnideria, Aquatic, radial symmetry, contain true tissues (nerve,muscle,digestive), and nematocysts (stinging cells), EX Hydra, jellyfish, (food source and production for animals). Platyhelminthes, known as flatworms, primitive animals that have bilateral symmetry and a brain, have organs for digestive and excretion but only 1 opening, EX Tapeworms, (some are parasites and cause diseases). Nematoda, worms are rounded, many are parasites, tubular bodies, tapered at both ends, digestive system is a tube, mouth and anus, reproduce sexually.
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Trophic breathing

Classified in Biology

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Biotic and Abiotic factors:

Ecosystem: all the living and nonliving parts of an environment.

Biotic factors: the living parts of an ecosystem.

Abiotic factors: the nonliving parts of an ecosystem.

Living things need non-living things to survive. Without food, water, and air, living things die. Sunlight (because provides energy that plants, and certain bacteria absorb to make their own food) shelter, and soil are also important for living things

Trees are biotic elements which need water that is an abiotic element. Without water the tree wouldn’t make oxygen, but without trees the water wouldn’t complete the water cycle.

Changes in abiotic factors can result in extreme problems for some organisms. For example, if a plant is adapted to low temperatures

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Classified in Biology

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Facial characteristics can be organised into three levels of facial features:

Level 1 details consist of gross facial characteristics that are easily observable. These include general geometry of the face and global skin colour. Such features can be used to quickly discriminate between a short round face and a long thin face, between predominantly male or female characteristics, and between faces from different races.Level 2 details consist of localised face information such as the structure of face components (e.G. Eyes), the relationship between facial components and the precise shape of the face. These features are essential for accurate recognition and require a higher resolution face image. The characteristics of local regions of the face... Continue reading "level" »

Aleosteric site

Classified in Biology

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A biomolecule that catalyzes chemical reactions

Absolute Specificity

The characteristic of an enzyme that it acts on one and only one substance

Relative Specificity

The characteristic of an enzyme that it acts on several structurally related substances

Stereochemical Specificity

The characteristic of an enzyme that it is able to distinguish between stereoisomers


The substance that undergoes a chemical change catalyzed by an enzyme

Inborn Error of Metabolism

A disease in which a genetic change causes a deficiency of a particular protein, often an enzyme


A nonprotein molecule or ion required by an enzyme for catalytic activity


An organic molecule required by an enzyme for catalytic activity


A catalytically

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Distogresion dental

Classified in Biology

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1) Tertiary crowding theories - lack of tooth wear, 3rd molar pression, late mandibular growth

2) Class II division 2 - MB cusp of U1M is medial to central sulcus of L1M; incr OJ; buccal displaced incisors
3)Increase arch length (therapeutic)- make most of leeway space; distal molar mvt; transversal expansion; incisor protrusion
4) Deep bite therapeutic tx - incisor intrusion; post. Segment extrusion; post. Segment eruption; buccal inclination of upper arches; surgery
5) Van der Linden classification- Type A (too much space); Type B (lack of space); Type C (more lack of space)
6) Class II division 2 - L1M is distal to U1M; UI retroclination; incr OB
7) Explain: 
Failure point- fracture/breaking point
Elastic limit- point in which if we release the
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Fixism theory

Classified in Biology

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Darwin and the theory of natural selection

The principal merit of Darwin's theory, in addition to the many evidence that he provided to it, is the discovery of the mechanism that governs the entire evolutionary process of species: the natural selection.

1) Firstly, when environmental resources become scarce, an inevitable competition occurs and, consequently, begin the struggle for survival in which most individuals die.

2) Secondly, it is also obvious that individuals of the same species have different features or characteristics that appear randomly and make individuals different each other.

 3) Third, these characteristics make some individuals more advantaged than others. Those whose characteristics are favourable to the demands of the environment... Continue reading "Fixism theory" »


Classified in Biology

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  • Have regular shape

  • Have cell wall, chloroplasts (most of the cells, but not all), a big vacuole

A. Cell Wall:

  • Made of cellulose

  • Only in plant cells

  • Helps to support and protect the cell

  • Fully permeable (even very large molecules are able to go through the cellulose cell wall)

B. Vacuole:

  • It is a space in a cell surrounded by a membrane and contain a solution of sugars and other substances called “cell sap”

  • Full vacuoles press outwards on the rest of the cell and help to keep it in shape

  • (animal cells contain much smaller vacuoles)

C. Chloroplasts:

  • Never found in animal cells

  • Present in Most of the plant cells

  • Contain “Chlorophyll” (absorbs energy from sunlight, and this energy is then used for making food for the plant by “Photosynthesis”

  • Often

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Functions that are over seen by the medulla

Classified in Biology

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Spinal cord.The spinal nerve divides into two roots.All the sensory fibres enter through the dorsal root and the motor fibres all leave through the ventral root.In the simplest reflex action,many nerve fibres,synapses and muscles are involved.All the cell bodies are concentrated in the grey matter.The withe matter consists of nerve fibres. Reflexes:bright light stimulates the light-sensitive cells of the retina.The nerve impulses in the sensory fibres from these receptors travel through the optic nerve to the brain. The brain:the medulla is concerned with regulation of the heart beat,breathing rate and temp.The cerebellum controls posture,balance and co-ordinated movement.The mid-brain deals with reflexes involving the eye.The cerebellum(
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