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

Structure of the Plasma Membrane

Membrane Amphipathic Properties

The plasma membrane is amphipathic:

• Fatty acid tails are hydrophobic (repel water).
• Phosphate head groups are hydrophilic (attract water).

Transport Through the Membrane

Factors Affecting Transport

• The concentration of substances.
• The type of molecules.

Transport Mechanisms

Based on these factors, transport can occur by three phenomena:

• Passive transport
• Active transport
• Vesicle-mediated transport

Passive Transport

In passive transport, molecules move down their concentration gradient: from regions of higher concentration to regions of lower concentration. The cell does not expend energy; the process occurs spontaneously.

Types of Passive Transport

• Simple diffusion
• Osmosis
• Facilitated diffusion

Simple

Nutrition, Mobility and Cell Characteristics

Nutrition

Nutrition: Variety — plants (autotrophs), animals (heterotrophs).

Mobility

Mobility: Variety — plants (immobile), animals (mobile).

Growth

Growth: Plants (often indeterminate / unlimited), animals (typically determinate / limited).

Cellular Coverings

Cell coverings: Plants: cell wall and cell membrane; Animals: plasma membrane.

Similarities of Living Beings

Similarities: assimilation, sensitivity, autoregulation and reproduction.

Cell Composition and Organelles

Cell composition: Life composed of abundant protoplasm; cells possess a cell membrane, cytoplasm, and a nuclear membrane (karyotheca) with a nucleus.

There are a variety of structures in the cytoplasm (organelles): ribosomes, endoplasmic

7-As nadadeiras dos peixes podem apresentar funções variadas de acordo com adaptações ocorridas ao longo dos tempos. Podem ser usadas para, exceto: Respirar

8- Na reprodução dos vertebrados inferiores, predominam os processos de: Fecundação externa

9-No Aparelho excretor dos peixes, os rins são do tipo: Mesonéfrico

1- Entre os peixes e os primeiros anfíbios foram necessários 40 milhões de anos de lenta e constante evolução.

Todas as alternativas contêm adaptações surgidas durante essa evolução, exceto : Manutenção da pele úmida, Termo regulação.

4- Os únicos animais que apresentam, ao longo da vida, respiração branquial, cutânea e pulmonar são os: Pererecas

7- um animal, vivendo no ambiente terrestre e utilizando a pele... Continue reading "Cola" »

Catabolism. breaking down of complex substances into simples ones to obtain energy.

Relative dating.is a way of using geometric relationship between rocks bodies to determine the sequence of geological events in an area.

Marine trangression. is a geologic events during which sea level rises relative to the land and the shoreline moves toward higher ground, resulting in floading.

Facies fossils. a fossil which exist only in a very specific environment. They show the original conditions of the position.

Anabolism. is the termi given to all the chemical reactions where simple substances are joines together to form more complex ones.

Mass extinction. is the extinction of one or more species in a short period of geological time, this is a consequences... Continue reading "Chemical oxygen generators are used to furnish oxygen to the" »

The Role of Microbiology in Biotechnology

Microbiology plays a crucial role in biotechnology, as it provides the foundational knowledge and techniques needed to manipulate microorganisms for various applications. Here are some key aspects of microbiology in biotechnology:

Key Aspects of Microbiology in Biotechnology

1. Microbial Diversity

Microbiology helps in understanding the vast diversity of microorganisms, including bacteria, viruses, fungi, and archaea. This knowledge is essential for selecting suitable organisms for biotechnological processes.

2. Genetic Engineering

Microorganisms like bacteria and yeast are commonly used in genetic engineering techniques. This involves modifying the genetic material of these organisms to produce desired traits,... Continue reading "The Role of Microbiology in Biotechnology: Applications and Advancements" »

Chemical Evolution

Chemical evolution refers to the processes that created the biomolecules, and then formed structures called protocells. According to Oparin, the first biomolecules were synthesized when the components of Earth’s primitive atmosphere reacted on contact with each other.

Biological Evolution

Biological evolution refers to the processes that led protocells to become different types of cells, and resulted in all the different organisms ever to have inhabited the Earth. Different types of prokaryotic cells were created from primitive cells: heterotrophic cells, photosynthetic cells, aerobic cells, long and very mobile cells.

Fixist Theories

Fixist theories uphold the idea that the species that currently exist on Earth were created... Continue reading "Chemical and Biological Evolution Theories and Characteristics of Hominids" »

Lower Canine

Root may bifurcate into 2 divisions

Chron:

• Enamel: 6-7 y.o
• Eruption: 9-10 y.o
• Root: 12-13 y.o

Geo:

• Lng/lab: pentagon/trapezoid, short side cervical

Mes-Dis:

• Triangular base cervical

Incis:

• Diamond

Labially:

• Cervical ridge/labial ridge/mes-dis development grooves

Lingually:

• Cingulum/lingual ridge/mes-des marginal ridge/1 lingual fossa

Mesial Contact:

• Incisal third

Distal Contact:

• Middle third

Pulp Cavity:

• 1 pulp horn/oval shaped transversally

Cusp Length:

• Distal side is longer

Upper First Premolar

Mesial Marginal Developmental Groove/Canine Fossa

Chro:

• Enamel: 5-6 y.o
• Eruption: 10-11 y.o
• Root: 12-13 y.o

Geo:

• Lng/Bucc: Trapezoid; short side cervical

Mes-Dis:

• Trapezoid; long side cervical

Occlu:

• Hexagonal

Buccally:

• Cervical/Buccal Ridge/Mes-Dis Buccal Developmental Groove

Mesially:

What Is an Enzyme?

An enzyme is a protein that acts as a biological catalyst. Its primary function is to increase the rate of a natural chemical reaction. Enzymes typically react with one specific substrate, and their activity is regulated within the cell through various means, including inhibitors and activators.

Enzyme Structure

Most enzymes are proteins with three-dimensional shapes determined by their specific amino acid sequences.

Key Concepts in Enzyme Activity

• Substrate: When a substrate molecule binds to the highly specific active site of an enzyme, an enzyme-substrate complex is formed. This complex modifies the substrate and initiates a series of chemical reactions, resulting in the formation of a product.
• Transition State: The highest

Food and Nutrition Fundamentals

Key Definitions

Nutrition

The study of nutrients in food, how the body uses them, and the relationship between diet, health, and disease. It involves taking in matter and energy to grow, survive, and reproduce; waste matter and waste energy are produced as by-products.

Food

Any solid or liquid substance consumed to provide nutritional support for an organism.

Nutrients

Compounds in foods essential to life and health, providing us with energy, the building blocks for repair and growth, and substances necessary to regulate chemical processes.

Types of Nutrients

Nutrients are classified into two main groups:

• Inorganic compounds: Water and mineral salts.
• Organic compounds: Carbohydrates, Fats (Lipids), Proteins, and Vitamins.