Notes, summaries, assignments, exams, and problems for Biology

Genome

Autotrophs and Heterotrophs Defined

F.5.1 Define the terms photoautotroph, photoheterotroph, chemoautotroph, and chemoheterotroph

Photoautotroph: An organism that uses light energy to generate ATP and produce organic compounds from inorganic substances.

Photoheterotroph: An organism that uses light energy to generate ATP and obtains organic compounds from other organisms.

Chemoautotroph: An organism that uses energy from chemical reactions to generate ATP and produce organic compounds from inorganic substances.

Chemoheterotroph: An organism that uses energy from chemical reactions to generate ATP and obtains organic compounds from other organisms.

Examples of Autotrophs and Heterotrophs

F.5.2 State one example of a photoautotroph, photoheterotroph,

Animal Respiration

Breathing is essential for respiration. Animals breathe by inhaling oxygen and exhaling carbon dioxide. This gas exchange occurs via the respiratory system.

Respiratory Systems

Respiratory systems require thin, moist surfaces covered in blood vessels for efficient gas exchange. This facilitates oxygen uptake and carbon dioxide expulsion.

Cutaneous Respiration

Gas exchange through the skin (thin and moist). Examples include earthworms and adult amphibians.

Branchial Respiration

Gas exchange through gills (surrounded by blood vessels). Examples include fish and some crustaceans.

Tracheal Respiration

Gas exchange via internal tubes (tracheae) carrying air directly to cells. Examples include terrestrial arthropods.

Pulmonary Respiration

Gas... Continue reading "Animal Respiration, Circulation, and Excretion" »

Evidence of Evolution

1. Anatomical and Morphological Evidence:

• Homologous organs
• Analogous and vestigial organs

Fossils reveal that organisms in the Earth's past were different from nowadays.

Some embryos from different species are similar, indicating an evolutionary relationship between them.

Biogeographical patterns can be explained according to theories of evolution.

Molecular similarities reveal the degree of relatedness between two groups.

• Parasites: organisms that live off other species.
• Behavior: based on genetic inheritance.

Present-Day Theories of Evolution

Neo-Darwinism considers that natural selection does not act on the individual in isolation... Continue reading "Evidence of Evolution and Present-Day Theories" »

Origin of Life Hypotheses

The Oparin-Haldane hypothesis suggests that life arose gradually from inorganic molecules, with "building blocks" like amino acids forming first and then combining to make complex polymers.

The primitive atmosphere was reducing, containing water vapor and ammonia.

Both Oparin and Haldane proposed that the first life forms were heterotrophs.

Oparin's Work with Coacervates

Oparin's work with coacervates confirmed that enzymes fundamental for the biochemical reactions of metabolism functioned more efficiently when contained within membrane-bound spheres than when free in an aqueous solution.

Haldane's Primordial Soup Idea

Haldane's ideas about the origin of life were very similar to Oparin's. Haldane proposed that the primordial... Continue reading "Origin of Life: Oparin-Haldane & Miller-Urey" »

The Senses of Hearing

5) THE SENSES OF HEARING:

6) THE HEALTH OF THE SENSE ORGAN:

Short-sightedness (myopia): distant objects appear out of focus because the eyeball is too long, so images are focused in front of the retina. Concave lenses or surgery can correct the problem.

Long-sightedness (hypermetropia): close objects appear out of focus because the eyeball is too short. This causes images to be focused behind the retina. Convex lenses or surgery can correct the problem.

Astigmatism: objects appear distorted or blurred. It is caused by an irregularly shaped cornea. Lens or surgery can correct the problem.

Cataracts: the crystalline lens loses its transparency until it becomes opaque. This causes progressive loss of vision and possible blindness.... Continue reading "The Senses of Hearing and Health of Sense Organs" »

These are energetic and structural substances found in many foods that we eat daily. There are two groups:

Simple Carbohydrates

• Monosaccharides: They are the simplest ones.
• Disaccharides: They are formed by two monosaccharides joined together.

Complex Carbohydrates (Polysaccharides)

They are neither sweet nor crystalline and they are not soluble in water. They include:

• Starch: It is made up of glucose molecules.
• Cellulose: It makes up vegetal fibre and forms the plant cellular wall. It is also made up of glucose molecules.

Inorganic Substances

These are small inorganic substances with variable composition. In solid state, they are structural. In dissolution, they are regulatory and allow our organs to function correctly and intervene in the regulation.... Continue reading "Energetic and Structural Substances in Foods" »

Pituitary

• Location: Head 2 lobes - anterior lobe
• Hormone: growth hormone
• Target organ: Whole body, skeleton
• Function: stimulate the growth

• Location: Head 2 lobes - anterior lobe
• Hormone: Thyroid stimulating hormone (TSH)
• Target organ: Thyroid
• Function: stimulate production of thyroid hormones

• Location: Head 2 lobes - anterior lobe
• Hormone: Gonadotropes. Follicle stimulating hormone (FSH) Luteinizing hormone (LH)
• Target organ: Ovaries and testes
• Function: action ovaries and testes

• Location: Head 2 lobes - anterior lobe
• Hormone: Adrenocorticotropic hormone (ACTH)
• Target organ: Adrenal glands
• Function: Stimulate the secretion of adrenal glands

• Location: Head 2 lobes - anterior lobe
• Hormone: Prolactin
• Target organ: breasts
• Function: stimulates breast growth and milk

The Significance of Meiosis

Why Meiosis?

 Meiosis generates diversity by ensuring that the gametes it gives rise to will differ genetically from one another.

 Meiosis is unlike regular cell division, or mitosis, which produces daughter cells that are exact genetic copies of parent cells.

 Evolution is spurred on by differences among offspring, and meiosis and sexual reproduction ensure such differences.

 By contrast, asexual reproduction, as is seen in bacteria and other organisms, produces organisms that are exact genetic copies, or clones, of the parental organism.

 The genetic diversity brought about by Meiosis and sexual reproduction is responsible, to a significant extent, for the great diversity of lifeforms seen in the living... Continue reading "Understanding Meiosis: The Process of Genetic Diversity and Reproduction" »

1.Which of the Following processes is endergonic?

the Synthesis of glucose from carbon dioxide and water

2.What is the Basic difference between exergonic and endergonic reactions?

Exergonic Reactions release energy; endergonic reactions absorb it.

3.Which of the Following examples is classified as a metabolic pathway?

protein Synthesis

4.When a cell Uses chemical energy to perform work, it couples a(n) ________ reaction with A(n) ________ reaction.

exergonic . . . Endergonic

5.The transfer Of a phosphate group to a molecule or compound is called

phosphorylation.

6.Anything that Prevents ATP formation will most likely

result in Cell death.

7.The energy Required to initiate an exergonic reaction is called

the energy Of activation.

8.Most of a Cell's enzymes