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

Protein Structure:

It is a three-dimensional structure. Polypeptides are folded to produce a globular shape. The structure is stabilized by intermolecular bonds between amino acids.

Primary Structure:

Is the sequence of amino acids in the polypeptide chain. It is codified by a gene. The sequence of nucleotides in a gene codify the sequence of amino acids in a polypeptide chain.

Secondary Structure:

3-dimensional conformation. It's the formation of beta-pleated and alpha helices, established by hydrogen bonds. It's the bond formed between the carboxyl group and the amino group.

Tertiary Structure:

The polypeptide chain is folded and established by interactions between R groups. The conformation is established by intramolecular bonds and interactions... Continue reading "Protein Structure and Functions" »

1. Challenges in Human Genetic Studies

The study of human genetics entails specific challenges, including:

• Limited offspring: Human couples have very few offspring, making it difficult to apply statistical methods.
• Long biological cycle: The human life cycle is long (approximately 15 years), requiring several decades to track specific traits across generations.
• Ethical constraints: We cannot plan crosses for individuals to determine their genotype due to ethical reasons.

2. The Human Karyotype

• A karyotype is the complete set of chromosomes of a species, providing information about their number, type, and structure.
• Karyotypes are derived from karyograms, which are images of all chromosomes in an individual. By comparing a person's karyogram to the

Polymerization –plus and minus ends of actin, Kd, critical concentration, phases of growth of polymers (lag, growth, and steady-state), nucleating factors, why growth occurs preferentially at plus end.

a.High Kd and Cc= ADP + Factin lower affinity actin so dissociate

b.Lower kd and Cc= Gactin/Factin + ATP higher affinity actin so dissociate

c.Profilin and thymosin: Profilin binds to (-) end = plus end grow fast

d.Thymosin buffer + actin monomer = prevent polymerization or ATP hydrolysis.

e.Actin monomer (is above Kd) & regulates actin filament assembly.

Arp2/3 comples to make a seed (nucleate) acting growth. Can create tree-like web

Myosin II structure: motor protein makes force in skeletal contraction muscles.

a.Heavy chain with NT head (ATPase... Continue reading "Cell Biology: Actin, Myosin, and Microtubules" »

Basic Nutrients

The human body is two-thirds water. Water is an essential nutrient that is involved in every function of the body. Water helps transport nutrients and waste products in and out of cells. Water is necessary for all digestive, absorption, circulatory, and excretory functions. Water is needed for the utilization of the water-soluble vitamins. It is needed for the maintenance of proper body temperature. It is recommended that you drink at least eight 8 glasses of water each day.

Dietary Recommendations

Carbohydrates

• It is recommended that about 60 percent of your total daily calories come from carbohydrates.
• If much of your diet consists of healthy complex carbohydrates, you should easily fulfill the recommended daily minimum of 25 grams

A Minimal pair is a pair of words that vary by only A single sound, usually meaning sounds that may confuse English learners, like The /f/ and /v/ infanandvan, Or the /e/ and /ɪ/ indeskanddisk

Minimal Pairs /ɪ/ and /i:/sit Seat

Minimal Pairs /e/ and /ɪ/desk disk

Minimal Pairs /e/ and /eɪ/wet wait

Minimal Pairs /æ/ and /ʌ/bat but

Minimal Pairs /əʊ/ and /ɔ:/sosaw

Minimal Pairs /ɒ/ and /əʊ/not note

Minimal Pairs /æ/ and /e/bad bed

Minimal Pairs /ɑ:/ and /ɜ:/fast first

Consonant Sounds

Minimal Pairs /b/ and /v/berryvery

Minimal Pairs /b/ and /p/buypie

Minimal Pairs /n/ and /ŋ/thinthing

Minimal Pairs /l/ and /r/alive arrive

Minimal Pairs /ʧ/ and /t/catchcat

Minimal Pairs /s/ and /ʃ/seashe

Minimal Pairs /f/ and /v/fanvan

Minimal Pairs /f/ and /h/

How Kidneys Work: Filtration and Waste Elimination

Solid waste products need to be dissolved in water to be eliminated from the body.

The Nephron: The Kidney's Functional Unit

Each kidney contains over a million functional units called nephrons, where the filtering process takes place.

Parts of the Nephron

• Bowman’s Capsule: Surrounds a tiny network of capillaries.
• The Tubule: Shaped like a handle, several nephrons empty into a large tube called a collecting duct.
• The Collecting Duct: Moves urine into the renal pelvis.

Kidney Function Process

1. Blood moves through the capillary networks where filtration occurs. Small molecules such as water, salts, glucose, and urea exit the bloodstream and enter Bowman’s capsule, forming the filtrate.
2. Some of the molecules

Four Types of Animal Tissues

1. Epithelial Tissue

• Squamous:
  • Simple: One cell thick; forms solid layers of cells.
  • Stratified: Multiple layers; forms the epidermis.
• Cuboidal:
  • Simple: One cell thick, roughly cube-shaped. Lines ducts where absorption and secretory activities take place.
• Columnar:
  • Simple: One cell thick, column-shaped. Lines the digestive tract.
  • Pseudostratified: Gives the appearance of more than one layer of columnar epithelial organs.

2. Connective Tissue

• Adipose: Honeycomb or chicken wire appearance. Stores energy, insulates, and supports and protects organs.
• Dense: Forms ligaments and the outer protective covering for bone.
• Bone: Tree ring-like appearance. Supports and protects, stores minerals and fat, and aids in blood cell production.

Essential Genetics Terminology

Conjugation: Genetic Material Transfer

Conjugation is the transfer of genetic material between unicellular individuals through direct cell-to-cell contact.

Bacterial Conjugation: Not Sexual Reproduction

Bacterial conjugation is often incorrectly regarded as the bacterial equivalent of sexual reproduction or mating.

Spermatogenesis: Male Sperm Development

Spermatogenesis is the process by which male spermatogonia develop into sperm cells.

Oogenesis: Female Egg Development

Oogenesis is the process by which female oogonia develop into egg cells.

Monohybrid Cross: Single Trait Inheritance

A monohybrid cross is a method of tracking the inheritance of a single trait from a pair of homozygous grandparents through generation F₁... Continue reading "Essential Genetics Terminology & Concepts" »

Cellular Development Stages

The early stages of development occur at the cellular, tissue, and organ levels of organization. At the cellular level, development includes cleavage, resulting in a multicellular embryo and the formation of a blastula.

Cleavage, which encompasses DNA replication and mitotic stages, is cell division without growth and results in a morula, a ball of cells. The next cellular stage is the formation of a blastula, a hollow ball of cells with a fluid-filled cavity called a blastocoel. The blastocoel forms when the cells of the morula pump Na+ into extracellular spaces, and water follows by osmosis.

Tissue Development Stages

The tissue stages of development are the early gastrula and the neurula. The early gastrula stage begins... Continue reading "Developmental Biology and Genetic Disorders" »

1) Respiratory Tract:

Passages through which oxygen enters the lungs and carbon dioxide is expelled.

• Nasal Passages: Air enters the nose and continues through these passages, where it is moistened and warmed. Dust and microorganisms in the air are retained here.
• Pharynx: Air from the nasal passages reaches the pharynx, which is part of both systems.
• Larynx: Made of cartilage. The vocal cords vibrate and enable humans to make sounds.
• Trachea: C-shaped cartilage rings through which air travels from the larynx to the bronchi.
• Bronchi and Bronchioles: Bronchi are two tubes that branch out from the trachea into each lung. They divide into small tubes called bronchioles, rounded sacs