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

General Plant Features

Plants are multicellular, autotrophic eukaryotes. They possess cell walls and chloroplasts, and they reproduce through both sexual and asexual means. Most are sessile.

Plant Classification

• Non-flowering plants: Mosses, liverworts, and ferns.
• Flowering plants: Gymnosperms (seeds not enclosed in fruit) and Angiosperms (seeds enclosed in fruit).

Mosses and Liverworts

These are small (approx. 1 cm), live in damp environments, and lack conducting vessels. They do not have true roots, stems, or leaves; instead, they have rhizoids (false roots), cauloids (false stems), and phyllodes (false leaves). They reproduce via spores. Liverworts have rounded leaves, while mosses have sharpened leaves.

Ferns

Ferns can grow to several meters in... Continue reading "Plant Biology: Classification, Nutrition, and Reproduction" »

Cytoplasm:

The cell space between the nuclear envelope and plasma membrane. Comprising cytosol, cytoskeleton, and organelles.

Cytosol:

The internal environment of the cytoplasm (75-85% water). It performs the synthesis of ribosomes and protids (enzymes, small molecules, or proteins). It forms filaments of the cytoskeleton. Due to the presence of many enzymes, there are numerous metabolic reactions.

Cytoskeleton:

In eukaryotes, it forms a network of protein filaments. Features:

• Maintaining the shape of the cell and the possibility of changing it.
• The possibility of moving the cell.
• Contraction of muscle.
• Transport and organization of organelles.

Microfilaments:

Actin filaments are the main components of the cytoskeleton. Usually, they partner with other... Continue reading "Understanding Cytoplasm and Its Key Components" »

Consumers in the Ecosystem

The power of consumers is derived from producers or other consumers. Within this group, there is a wide variety of species, ranging from small zooplankton to large predators. It is evident that consumers (heterotrophs) depend directly or indirectly on producers.

Trophic Levels

• Primary Consumers (First Order): Animals that consume plant organisms, such as cows, horses, lobsters, and giraffes.
• Secondary Consumers (Second Order): Animals that eat primary consumers, such as foxes, frogs, tigers, and eagles.

Every living organism is a link in the chain. Generally, each chain has two to six links, but they rarely possess a greater number.

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" »