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

Porifera and Cnidarians: Structure

Porifera (sponges) and Cnidarians (anemones, corals, and jellyfish) are simple, aquatic invertebrates.

Porifera (Sponges)

• Mostly marine, some freshwater species
• Bag-shaped body with pores that communicate with the atrial cavity
• The atrial cavity connects with the exterior through the osculum
• High capacity for regeneration

Cnidarians

• Anemones, corals, and jellyfish (all marine), hydra (freshwater)
• Radial symmetry
• Soft body with a single opening surrounded by tentacles
• Stinging cells (cnidocytes)
• Gastrovascular cavity that functions as a stomach
• Carnivorous
• Two forms:
  • Polyps: Tubular, bag-shaped with the opening at the top
  • Medusae: Umbrella-shaped, actively swim or float in the water

Worms: Platyhelminthes, Nematodes, and Annelids

Worms... Continue reading "Invertebrate Animals: Characteristics and Classification" »

Perineum Anatomy

Perineum Structures

The perineum is a diamond-shaped space between the pubic symphysis (anteriorly), the coccyx (posteriorly), and the ischial tuberosities (laterally), lying just inferior to the pelvic diaphragm (levator ani and coccygeus).

It is divided transversely into two triangles:

• The anterior is the urogenital triangle, which includes the external genitals.
• The posterior is the anal triangle, which contains the anus.

The perineum is also divided into superficial and deep layers, with some muscles common to men and women.

Muscles of the Perineum and Pelvic Floor

Muscles making up the Urogenital and Anal (Pelvic) triangles/diaphragms include:

• Urogenital diaphragm: Superficial and intermediate planes
• Sphincters: Internal and external

Lab 8: Temperature and Microbial Growth

Key Concepts

• Psychrophiles grow best between 0–20°C. Often found in cold environments like glaciers.
• Mesophiles prefer 20–45°C. These include human pathogens like E. coli.
• Thermophiles thrive at 55°C or higher. They are often found in hot springs.

Materials and Their Functions

• Tryptic Soy Broth (TSB): A nutrient-rich medium that supports bacterial growth.
• Incubators set to different temperatures (4°C, 25°C, 37°C, 55°C): Used to simulate environmental conditions.
• Spectrophotometer (OD600): Measures turbidity (cloudiness) of a culture to estimate cell density.
• Classification by growth: “+++” indicates heavy growth; “0” means no growth.

In this lab, students investigated how temperature affects... Continue reading "Microbiology Lab Fundamentals: Growth, Metabolism, Genetics" »

Insect Defenses Against Predators

Three Plant Mechanisms to Defend Against Insects

• Physical: Thick walls
• Chemical: Phytochemicals that kill insects
• Entrapment: Pitcher plants

How Insects Overcome Physical Defenses

• Specialized mandibles
• Evolution
• Immunity to phytochemicals
• Specialization to survive the digestive liquid of pitcher plants

Insect Parasitism

Endoparasites

Approximately 20% of insect orders include endoparasites. Some orders that include endoparasites are:

• Hymenoptera
• Diptera
• Strepsiptera

Ectoparasites

Some orders that include ectoparasites are:

• Anoplura
• Mallophaga
• Siphonaptera

Three Challenges Faced by Endoparasites

• Respiration
• Excretion/getting rid of toxic nitrogenous waste without killing the host
• Avoiding the host's endocrine system

Insect Social Behavior

Subsocial

पारिभाषिक शब्दावली: अर्थ और स्वरूप

अर्थ

पारिभाषिक शब्दावली से तात्पर्य ऐसे शब्दों से है जिनका प्रयोग किसी विशेष विषय, क्षेत्र या विद्या में एक निश्चित और स्थिर अर्थ में किया जाता है। ये शब्द उस क्षेत्र की तकनीकी भाषा का हिस्सा होते हैं और सामान्य बोलचाल की भाषा से अलग होते हैं।

उदाहरण

• गणित

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" »

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: