Biology Flashcard (Science Bowl)

T Cell Activation: The process of turning T cells into effector T cells from Naive T cells.

Antigen Receptor: The protein in which recognition of an antigen occurs.

Antigen Presentation: The display of foreign fragments to activate T cells.

Types of T Cells

• Immature CD4+ or Helper T cell

• Immature CD8+ or Cytotoxic T cell

Activation

• The APC presents antigen molecules through the MHC I on its surface. This interacts with CD8+ T cell receptors (CD4+ T cells interact with MHC II)

T Cell Activation Signals

• There are two important signals for T cell activation and one accessory signal (not as important)

• Signal 1: The recognition of an MHC molecule antigen from an APC.

• Signal 2: Co-stimulatory molecules are recognized by the T cell (CD28 T cell to CD80 or CD86 APC) (If this signal is not present, the cell goes into apoptosis).

• Signal 3: Cytokines are produced to activate the T cell

Development: The changes an organism undergoes as it grows older.

Fertilization: The formation of a diploid zygote from a haploid egg and sperm.

Acrosome: A special vesicle on the top of the sperm head that holds hydrolytic enzymes.

Polyspermy: The entry of multiple sperm nuclei.

Cortical Reaction: The reaction is believed to be caused by increased Ca^2+, which provides long-term prevention of polyspermy by fusing cortical granules.

Cleavage: a series of cell divisions during development.

Blastomeres: Smaller cells that are the result of cleavage.

Blastula: A hollow ball of cells from the first five to seven cleavages.

Blastocoel: The fluid-filled cavity surrounded by the blastula.

Morphogenesis: The process in which an animal's body develops over time during embryonic development.

Gastrula: Two or three-layered embryos created through gastrulation.

Diploblasts: Embryo with two layers.

Triploblasts: Embryo with three layers.

Germ Layers: The cell layers produced in gastrulation.

Ectoderm: The layer that forms on the outer gastrula.

Endoderm: The layer that forms on the inner gastrula.

Mesoderm: The layer that forms between the ectoderm and endoderm in triploblasts.

Organogenesis: The development of the rudimentary organs in the embryo.

Neurulation: The process in which the neural plate forms the neural tube by folding in on itself.

Induction: A process in which a group of cells or tissue influences the development of other groups through close interactions.

Hox Genes: Master regulatory genes that control the positional identity of an embryo.

Steps of Embryonic Development

I Fertilization

An acrosomal reaction occurs when the sperm makes contact with the egg.

The acrosome discharges hydrolytic enzymes.

The enzymes digest the egg jelly coat allowing for the acrosomal process and fusion to begin.

This begins fertilization, a process that speeds up metabolic reactions to bring embryonic development. The cell is now activated.

II Cleavage

During cleavage, phases G₁ and G₂ are essentially skipped. Only phases S and M take place.

The first five to seven cleavages result in a blastula.

Holoblastic Cleavage: In this cleavage, cleavage passes through the entire egg (found in echinoderms, mammals, and annelids)

Meroblastic Cleavage: In this cleavage, the volume of the yolk is so great that a cleavage furrow cannot pass through it. The region lacking yolk goes through cleavage as a result.

III Gastrulation

During this stage, a set of cells move into the blastocoel. This then leads to cell layers and a digestive tube to be formed.

Ectoderm = nervous system, skin, and pituitary gland

Mesoderm = skeletal and muscular systems, circulatory and lymphatic systems.

Endoderm = digestive tract and organs, thymus, thyroid, and parathyroid.

IV Organogenesis

During this stage, the regions of the germ layers develop into the rudimentary organs.

Neurulation will be an example of how different cells are fated for certain roles in development (Neurulation is the first step in organogenesis).

Neurulation begins as cells in the dorsal mesoderm form the notochord. Signaling molecules are released from these cells to create a neural plate in the ectoderm (This is an example of induction).

The neural plate folds inwards and forms the neural groove which eventually forms the neural tube.

This tube will give rise to the neural tube. The neural tube is the foundation for the brain and the spinal cord

Human Eggs: Small eggs with little food reserve.

Oviduct: The tube where fertilization occurs, between the ovaries and uterus.

Cleavage: The division of the fertilized egg into multiple cells.

Blastocyst: Hollow ball of cells formed after cleavage.

Inner Cell Mass: The group of cells within the blastocyst that will develop into the embryo.

Trophoblast: Outer layer of the blastocyst responsible for implantation.

Endometrium: Lining of the uterus that the blastocyst embeds into.

Epiblast: Inner layer of cells in the inner cell mass that will form the embryo.

Hypoblast: Outer layer of cells in the inner cell mass that supports the development.

Extraembryonic Membranes: Membranes that surround and support the embryo.

Placenta: Organ that allows nutrient, gas, and waste exchange between mother and embryo.

Fertilization occurs in the oviduct where the sperm and egg fuse. Development begins after fertilization.

After fertilization, the embryo begins its journey to the uterus, completing development as it travels.

Cleavage divides the embryo into over 100 cells, forming a blastocyst with an inner cell mass.

The blastocyst travels to the uterus and forms a cluster of cells at one end, known as the inner cell mass.

The inner cell mass forms the actual embryo, with the surrounding trophoblast aiding in implantation.

The trophoblast secretes enzymes to break down the endometrium and facilitates implantation into the uterus.

Implantation occurs when the blastocyst embeds into the endometrium, beginning the next stage of development.

After implantation, the epiblast forms the ectoderm, mesoderm, and endoderm, which are the three germ layers.

The hypoblast contributes to the formation of extraembryonic tissues, such as membranes, to protect and support the embryo.

These extraembryonic membranes surround the embryo and support its growth, also forming structures like the placenta.

The placenta forms from the epiblast, trophoblast, and endometrial tissue, facilitating nutrient exchange and waste removal.

Heredity: The passing of traits from parents to their offspring, with variations in traits caused by genetic factors.

Allele: Different versions of a gene.

Homozygous: Having two identical copies of a gene.

Heterozygous: Having two different copies of a gene.

Genotype: The genetic composition of an individual that creates all of their traits.

Chromosomes: The bundle form of DNA that is used to pass down traits.

Polygenic Trait: A trait that is expressed due to the presence of multiple genes.

Mendelian Trait: A single trait that is expressed by a single gene.

Pleiotropic Gene: A single gene that controls how multiple traits are going to be expressed.

Heredity

Gregor Mendel

Long ago, people had already realized that offspring usually had the same traits as their parents. However, no one knew exactly how or why this occurred.

Gregor Mendel is considered the father of heredity and classical genetics. He experimented on pea plants in his garden and discovered the framework of how traits get passed from one generation to the next.

Classical Genetics

This part of genetics includes the ideas Mendel had about how traits are passed down.

In your chromosomes, many genes express your traits.

All cells other than reproductive cells (Gametes) are diploid and receive two copies of each chromosome, one from each parent. The chromosomes are not identical, allowing for variation of your traits.

Law of Dominance: The law that states that dominant alleles in heterozygous genotypes will mask the expression of the recessive allele, resulting in the dominant phenotype being expressed.

Law of Segregation: The law that states individuals possess two alleles and a parent only passes one of his/her alleles to their offspring.

Heredity Probabilities

Homozygous Dominant (AA) with Homozygous Recessive (aa) = 100% Dominant, 0% Recessive

2 Heterzygous (Aa) = 75% Dominant, 25% Recessive

Heterozygous (Aa) with Homozygous Recessive (aa) = 50% Dominant, 50% Recessive

Heterozygous (Aa) with Homozygous Dominant (AA) = 100% Dominant, 0% Recessive

Punnet Squares

Punnet squares can be used to determine the probabilities of traits passed down to the offspring of parents.

It works by identifying the possible outcomes of a dominant and recessive gene. The pairs of genes are crossed on a table showing the possibilities. You can then check the possibility of an offspring receiving either a dominant or recessive gene (Remember: Dominant genes will always be expressed over recessive genes).

Evolution: The change of a population’s inherited traits over time.

Population: A group of organisms in the same species in the same place.

Gene Flow: Genes that move through a different population

Genetic Drift: The change in genes caused by a random event

Natural Selection: A process that favors the traits needed in an environment.

Evolution happens between populations, not individuals. Each member of a population has different traits.

Mechanisms that cause changes in the population’s traits can lead to evolution.

Different Evolution Mechanisms

Gene Flow allows for genes to be transferred from one population to the next. Genes can mutate and create new genes.

Genetic drift can change the gene pool of an entire population due to random chance.

Natural Selection makes it so that a gene pool that is fit for the environment survives.

Evidence for Evolution

Shared common ancestry creates many similarities between organisms. These are called homologies.

DNA homologies are the biggest evidence for evolution. Different species in different areas still share similar genes due to common ancestors.

Another homology is in anatomy. Different species have similar anatomy, suggesting that they are related (e.g., human forearm and dog forearm).

Vestigial structures were passed down from an ancestor but have no use now. This is huge evidence for evolution as it shows how an organism develops over time.

Developmental Homologies show similarities in the development of related species. This suggests that these species are related and have their developmental processes passed down.

Fossil Records

Fossil records show the remains of long-lost organisms. They can show how a population's characteristics have changed over time.

Biogeography

This field of science studies how organisms are spread out around the planet and the relationships of these organisms in different areas. This field of science provides evidence that changes in location act to change a species.

Taxonomy: The branch of biology that deals with classifications of animals, plants, and microorganisms.

Phylogeny: The evolutionary history of a species.

Cambrian Explosion: A period of rapid evolution where most of the major phyla appeared in the fossil record (541-530 million years ago).

Tree of Life: A diagram that shows the evolutionary relationship between all living things.

Miller-Urey Experiment: A chemical experiment that simulated the conditions of Earth that allowed for the formation of biomolecules.

Important Phyla

• Chordata (Vertebrates and animals with a notochord during development (eg Mammals, Birds))

• Arthropoda (Animals with jointed appendages and armor made of chitin (Bugs/Creepy Crawlies))

• Anthophyta (Magnoliophyta) (Plants that produce flowers) (Divided into two groups: Monocots (eg: Grasses, Lilies) and Dicots (eg: Roses, Beans)

Tree of Life

The truck of the tree represents the unicellular origins of life.

The branches of the tree represent the different organisms created by centuries of evolution.

Major Divisions of Animalia

• Sciecies

• Genus

• Family

• Order

• Class

• Phylum

• Kingdom

• Domain

All organisms belong to a certain species. These are populations that have sufficient genetic similarities for reproduction and produce

viable offspring.

Origins of Life

The origins of life can be traced 4 billion years ago. The Miller-Urey simulated how Earth was when it had cooled down enough for liquid water to exist. This allowed for nitrogenous bases and amino acids to form spontaneously.

The amino acids and nitrogenous bases polymerized to form long chains. The chains, by chance, were enclosed in self-generating membranes creating the first protocells.

When nucleic acids became self-replicating, inheritance took hold.

History of the Earth

Hadean Eon

• 4.6 to 4 billion years ago

• Earth was a hot ball of molten rock

Archean Eon

• 4 to 2.5 billion years ago

• Prokaryotic life arose

• They lived alone for 1.5 billion years

• The period where Earth became covered in oxygen due to photosynthesis

Proterozoic Eon

• 2.5 billion to 541 million years ago

• The period of time where eukaryotic life emerged through endosymbiosis

• Multicellular life evolved during this time through cell specialization

Cambrian Explosion

• 541 million years ago

• The period of time when animals appeared

Phanerozoic Eon

• 541 million years ago to today

• Split into three sections (Paleozoic Era (541 m to 252 m BC, Mesozoic Era (252 m to 66 m BC), and Cenozoic Era (66 m BC to today).

• Starts just before animals reach dry land

• Dinosaurs lived during the Mesozoic era

• Humans arrived in the last part of the Cenozoic Era (Pleistocene Epoch).

• The eras are separated by huge extinction events.

Phylogeny

Major Divisions of Animalia

• Sciecies

• Genus

• Family

• Order

• Class

• Phylum

• Kingdom

• Domain

Domains are the most basic categorizations of life. It includes

• Bacteria

• Archaea

• Eukarya

The next classification kingdoms come from the different types of eukarya. These kingdoms include:

• Animalia (All animals)

• Plantae (All Plants)

• Fungi (All Fungi)

• Protista (All Protists) (Many biologists do not recognize protists as an actual kingdom)

In each kingdom, there are several phyla. This includes:

Animal Phyla

• Arthropoda (Animals with jointed appendages, armor made of chitin (Bugs/Creepy Crawlies))

• Mollusca ( ) eg Snails/Octopus and other such animals)

• Chordata (Vertebrates and animals with a notochord during development (eg Mammals, Birds))

• Cnidaria (Animals with special stinging cells (eg, Jellyfish, Man of War)

• Annelida (Animals with segmented bodies (eg, Worms)

Plant Phyla

• Bryophyta (Mosses) (Plants that are small, soft, and nonvascular (eg, Peat Moss))

• Anthophyta (Magnoliophyta) (Plants that produce flowers) (Divided into two groups: Monocots (eg, Grasses, Lilies) and Dicots (eg, Roses, Beans)

All cells are made up of proteins, lipids, nucleic acids, and carbohydrates (Macromolecules).

Phospholipids have polar heads and non-polar fatty acid tails.

Cell Compartmentalization

Cells are organized into subcellular components

Members of the endomembrane system

• Lysosomes

• Nuclear Envelope

• Vesicles

• ER

• Golgi Complex

• Plasma Membrane

Rough ER

• Contains ribosome

• Produces and folds proteins

• Aids in intracellular transport

Smooth ER

• Rids waste

• Synthesizes lipids

Mitosis: The division of somatic (body) cells

Connective Tissue: Tissue that supports, protects, and binds other tissues. Has an abundant extracellular matrix.

Function of Connective Tissue: Provides structural support, stores energy, transports materials, and connects tissues.

Tendons: Connective tissue that connects muscle to bone.

Ligaments: Connect bone to bone.

Cartilage: Connective tissue that provides flexible support (e.g., nose, ear, joints).

Mesenchyme: A loose fluid-like embryonic tissue in which connective tissue originates.

Extracellular Matrix: The main component of connective tissue that is located outside the actual connective tissue cells and is made of nonliving materials

Ground Substance: A watery unstructured material that fills in the space between cells.

Fibers: Molecules that give support and shape to the ground substance

Glandular Epithelium: A type of tissue that secretes substances (e.g., hormones, enzymes).

Simple Epithelium: A single layer of the epithelial cells that allow diffusion, filtration, or secretion (e.g., lung alveoli, kidney tubules).

Stratified Epithelium: Protects underlying structures (e.g., skin, mouth lining).

Function: Produces movement through contraction, maintains posture, and generates heat.

Skeletal Muscle: Moves bones and allows voluntary movement.

Cardiac Muscle: Pumps blood through the heart and circulatory system.

Smooth Muscle: Moves substances through the digestive tract and regulates blood flow.

Nervous Tissue Function: Sends and receives electrical signals to control body functions.

Neurons: Cells that transmit electrical impulses to process and relay information.

Glial Cells: Cells that support and protect nerve cells in the brain and nervous system.

Central Nervous System (CNS): The part of the nervous system that consists of the brain and spinal cord.

Peripheral Nervous System: The part of the nervous system that consists of nerves connecting the body to the CNS.

Connective Tissue

Connective tissue is the most abundant tissue type, showing up almost everywhere in your body.

Loose connective tissue is very open and is found in ligaments. Dense connective tissue is found in tendons, and is tightly packed together.

Types of connective tissue

• Proper

• Cartilage

• Bone

• Blood

Fat is a type of connective tissue that provides insulation and fuel storage.

The bones, tendons, and cartilage bind, support, and protect your organs and make up your skeleton.

Your blood transports nutrients and materials throughout the body.

Unique Aspect of Connective Tissue

• Share the same origin (Mesenchyme)

• Different degrees of vascularity (Blood flow)

• Mostly composed of nonliving material (Extracellular Matrix)

The main components of the extracellular matrix include the ground substance and a multitude of fibers

The ground substance is made of

• Starch

• Protein molecules (Proteoglycans (glycosaminoglycans (GAGs)))

• Water

Fibers come in many types

• Collagen Fibers - strongest and most abundant type of fiber

• Elastic Fibers - form a branching framework and stretch like rubber bands

• Reticular Fibers - short, finer collagen fibers that form sponge-like networks

Types of connective tissue cells

Blast cells

These types of cells are immature stem cells that are specialized to form the specific ground substance and fibers for their specific connective tissue (For example: Osteoblasts and Chondroblasts).

Cyte Cells

These cells are mature connective tissue cells after the blast cells have created their ground substance or fiber (For example: Osteocytes and Chondrocytes). They maintain the health of the matrix after its creation.

Epithelial Tissue

Covers body surfaces, lines cavities, and forms glands. Cells are tightly packed with little extracellular matrix.

Found in layers: simple (one layer) and stratified (multiple layers).

Stratified epithelium provides protection in high-friction areas (e.g., skin, esophagus). Simple epithelium is used in areas where things need to be absorbed (e.g., kidney, stomach).

There are three structures of epithelial cells: cuboidal (cube-shaped), squamous (flat), and columnar (tall and rectangular).

Muscle Tissue

Responsible for movement. Made of elongated cells (muscle fibers) that contract.

There are three types of muscle tissue: skeletal, cardiac, and smooth muscle.

Skeletal muscle is voluntary, connected to the muscle, and is used for movement.

Cardiac muscle is Involuntary, striated, and found in the heart. It has intercalated discs for coordination.

Smooth muscle is involuntary, non-striated, found in the walls of organs and blood vessels.

Nervous Tissue

Composed of neurons and supporting cells. Found in the brain, spinal cord, and nerves.

Neurons are the main signaling cells. They contain dendrites that receive signals and axons that send signals.

Glial cells (Neuroglia) are nervous system immune cells that support, nourish, and protect neurons.

Neuron: The basic subunit of the nervous system that controls

Basic Subunit of the Nervous System (Neuron)

Integumentary System: The body's outer layer that keeps boundaries and regulates the body’s homeostasis.

Functions and the How of the Integumentary System:

Protects Deeper Tissues from:

Mechanical Damage (Bumps) - The physical barrier contains keratin, which toughens cells; fat cells to cushion blows; and both pressure and pain receptors, which alert the nervous system to possible damage.

Chemical Damage (Acids and Bases) - Has relatively impermeable keratinized cells; contains pain receptors, which alert nervous cells to possible damage.

Microbe Damage - Has an unbroken surface and “acid mantle” (skin secretions are acidic and thus inhibit microbes, such as bacteria). Phagocytes (Langerhans Cells) ingest foreign substances and pathogens, preventing them from penetrating deeper body tissues.

Ultraviolet (UV) radiation (Damaging effects of sunlight or tanning beds) - Melanin produced by melanocytes offers protection from UV damage.

Thermal (heat or cold) damage - Contains heat/cold/pain receptors.

Desiccation (drying out) - Contains a water-resistant glycolipid and keratin.

Aids in body heat loss or heat retention (controlled by the nervous system) - Heat loss: By activating sweat glands and by allowing blood to flush into skin capillary beds so that heat can radiate from the skin surface. Heat Retention: By not allowing blood to flush into skin capillary beds.

Aids in excretion of urea and uric acid - Contained in perspiration produced by sweat glands

Synthesizes vitamin D - Modified cholesterol molecules in skin converted to vitamin D in the presence of sunlight

The integumentary system is responsible for keeping the boundaries of the body and maintaining homeostasis.

The organs and tissues included in this system include the:

Skin

Hair

Fingernails

Glands

The Skin

The skin has multiple layers that protect the body, regulate body temperature, and excrete excess waste. The skin is the largest organ in the body.

Layers of the skin

Epidermis

• The epidermis is the outermost layer. It creates our skin tone.

• They are made up of keratinocytes. Keratinocytes produce a protein called keratin that makes the epidermis so tough.

• The epidermis is avascular and does not receive blood on its own.

• Comprised of its own five layers (Corneum, Granulosum, Lucidum, Spinosum, Basale).

• The cells in the top of the epidermis are dead as they are cornified.

Stratum Corneum

• The outermost layer

• Made up of 20-30 dead keratinocyte cells

Stratum Lucidum

• Second layer

• Hold two or three rows of clear, dead keratinocytes

• This layer is only found in the thick skin areas of the palms and the soles of the feet.

Stratum Granulosum

• Third layer

• Contains living keratinocytes that produce tons of keratin

Stratum Spinosum

• Fourth layer

• Contain filaments that hold the cells together

Stratum Basale

• Last and deepest layer

• Where the production of future keratinocytes occurs

Dermis

• Underneath the epidermis

• Made up of connective tissue

• Contains the bases of hair follicles

• Consists of two made regions, the papillary and reticular areas.

• The Papillary Layer is the superficial dermal region.

• The Reticular Layer is the deeper layer of the dermis. It is made up of irregular connective tissue, as well as blood vessels, sweat, and oil glands.

• Collagen and elastic fibers are found throughout the dermis. The college makes the dermis tough and binds water to keep the skin hydrated. The elastin makes the skin flexible.

• Fingerprints are located in the papillary layer of the dermis and are made by sweat.

Hypodermis

• The lowest layer of the skin

• Composed mostly of adipose and fatty tissue

Short Bones: Roughly cube-shaped bones with the same length, width, and thickness dimensions.

Long Bones: Long dense bones that have a shaft and two ends.

Joints: Where two bones are connected.

Important Bones

Skull (Scientific name: Cranium)

Collarbone (Sciencetific Name: Clavical)

Breastbone (Scientific Name: Sternum)

Upper Leg Bone (Scientific Name: Femur)

Lower Leg Bone (Scientific Name: Tibia)

Upper Arm Bone (Scientific Name: Humerus)

Lower Arm Bone (Scientific Name: Radius)

Backbone (Scientific Name: Vertebrae)

Osteoclast: A type of cell that breaks down bone to release calcium into the blood.

Osteoblast: A type of cell that builds new bone.

Osteocyte: A type of bone cell that connects to other osteocytes to form bone tissue.Con

Skeleton Anatomy

The skeleton is split into two sections, the axial skeleton and the appendicular skeleton.

Axial Skeleton

• Skull

• Ribs

• Spinal Column

• Sternum

Spinal Column

The spinal column or vertebral column consists of 33 vertebrae (Some vertebrae fuse as you age). There is also an intervertebral disk between most vertebrae.

The first vertebrae is called the atlas and the second is called the axis. The first 7 are called the cervical vertebrae. The next 12 are called the thoracic vertebrae. The next five are the lumbar vertebrae. The last 10 are called the sacral and coccyx vertebrae (These vertebrae fused to create 1 sacrum and 1 coccyx).

As you go down the spinal column, the vertebrae get thicker.

Thus in size and thickness:

Cervical < Thoracic < Lumbar < Sacral

Rib Cage

Consists of 24 ribs, each making 12 pairs.

Classification of ribs

• 7 pairs of true ribs

• 5 pairs of false ribs

• 1 pair of floating ribs

Appendicular Skeleton

• Shoulder Girdle

• Arm Bones

• Pelvic Girdle

• Leg Bones

Shoulder Girdle

Comprised four bones, two clavicle bones, and 2 scapulas.

Arm

Comprised of three bones, the upper bone (humerus), the radius, and the ulna.

At the bottom of the arms are the hand bones.

They are comprised of

• 8 carpals (wrist bones)

• 5 metacarpals

• 14 phalanges (finger bones)

Pelvic Girdle

This is the structure in which the leg bones are attached.

It is comprised of 2 ox coxae (hip bones). Each hip bone is divided into three sections, the ilium, the ischium, and the symphysis (pubic bone).

Leg Bone

These bones are attached to the pelvic sockets (acetabulums).

Each leg is comprised of one femur, one fibula (shin bone), and one tibia. There is also an in-between bone called the patella (knee cap).

At the bottom of the legs are the feet’ bones

They are comprised of

• 7 tarsals (ankle bones)

• 5 metatarsals

• 14 phalanges (toe bones)

Skeleton Physiology

The skeletal system is tasked with keeping the body structured and intact. They give the body the structure for it to move.

The skeleton protects the important organs of the body from damage and trauma.

Spinal Column

• Protects the spinal cord.

• Intervertebral disks act as shock absorbers between the vertebrae.

Rib Cage

• Protects vital organs such as the heart, lungs, and major blood vessels.

• Also responsible for the production of blood (hematopoiesis).

Long Bone Anatomy

The two ends located on a long bone are called epiphyses. The top epiphysis is called the proximal epiphysis and the other one is called the distal epiphysis.

The shaft of the long bone is called the diaphysis. This part of the bone gives support and leverage for movement.

The outer shell of the long bone is made of cortical bone (compact bone). Beneath that layer is the cancellous bone.

Short Bone Anatomy

Short bones are also made up of cortical and cancellous tissue.

Long Bone Physiology

Long bones support the body’s load during daily activities. They are essential for the mobility of the skeleton.

Short Bone Physiology

Support areas with a lot of physical activity or areas that need extra protection.

Osteoclasts, Osteoblasts, and Osteocytes

Osteoclasts

• Break down bone

• This cleans and prunes the bone

• Come from the bone marrow

Osteoblasts

• Builds new bone

• This strengthens the bone

• The new bone they create is called osteoid

• The osteoid is made up of collagen and other proteins

• Controls calcium and mineral deposition

Osteocytes

• Connect and form bone tissue

Endocrine System: The organ system that produces, releases, and reabsorbs hormones.

Hormones: A regulatory substance that controls the actions of target cells.

Cascades: When hormones trigger the release or power the effect of other hormones.

Gland: Any structure that makes and secretes hormones.

Target Cell: Any cell that a specific hormone is intended for.

Types of Hormones and Their Functions

Adrenaline: Increase systolic blood pressure, glycogenolysis, lipolysis, increase cardiac output, influence goosebumps, etc.

Melatonin: Managing sleep–wake cycle

Dopamine: Regulation of cellular cAMP levels, prolactin antagonist (gives feelings of pleasure and satisfaction)

Hormones control almost all cells in the body. They regulate:

• Reproduction

• Metabolism and Energy Balance

• Growth and Development

• Body Defenses

• General Homeostasis (Water, Nutrient, and Electrolyte balance of blood)

The endocrine system is similar in ways to the nervous system. Both systems monitor and respond to changes within the body, just in different ways.

Organs of the Endocrine System

The endocrine system is made up of glands that produce and release the hormones. The main gland is the pituitary gland.

There are also a few organs associated with this system.

Pituitary Gland

This gland produces a plethora of hormones that trigger other glands like the thyroid, parathyroid, adrenal, and pineal glands to release their hormones.

Hormones

Hormones can only trigger reactions in specific cells. These are called the target cells.

Chemically, most hormones are made up of amino acids. Others are made from lipids. This structure determines if the hormone is water soluble or lipid soluble.

Water-soluble hormones cannot get across the cell membrane by themselves. Target cells for these hormones have receptors on the surface of the membrane that bind to their specific hormone. Lipophilic hormones can “glide” across the cell membrane, so their receptors are located inside the target cell.

The hormone alters the physiology of the target cell once it has activated it. Some of the cell functions are either increased or decreased.

Vitamin: Organic compounds that are required for growth and nutrition and are required in small quantities.

Fat Soluble Vitamins: Vitamins that dissolve in fats and oils and are stored in the body’s fatty tissue and liver. (Fat-soluble vitamins are hydrophobic and lipophilic)

Water Soluble Vitamins: Vitamins that are dissolved in water and carried to the body tissue (They are not stored in the body).

Vitamin A (Retinol, Beta-Carotene): A fat soluble vitamin that is related to retinol.

Vitamin D (Calciferol): A fat-soluble vitamin that is synthesized by the skin.

Vitamin E (Phylloquinone, Menaquinone): A group of eight related compounds in molecule structure that include four tocopherols and four tocotrienols.

Fat Soluble Vitamins:

Vitamin A

• Essential for vision

• Supports immune function

• Promotes cell growth and differentiation.

• Is found in liver, fish, dairy, and eggs.

Vitamin D

• Helps the body absorb calcium and phosphorus, crucial for bone health.

• Supports immune function and reduces inflammation.

• The body synthesizes vitamin D in the skin with special cholesterol that turns into the active form of this vitamin (calcitriol) when in contact with sunlight.

Vitamin E

• Acts as an antioxidant, protecting cells from oxidative stress.

• Supports immune function and skin health.

• Prevents red blood cell damage.

• Found in nuts and seeds (almonds, sunflower seeds), vegetable oils, and spinach.

Vitamin K

• Essential for blood clotting (activates clotting factors).

• Supports bone metabolism and heart health.

• Found in leafy green vegetables (kale, spinach), broccoli, and fermented foods.

• Gut bacteria also synthesize some Vitamin K.

Water-Soluble Vitamins

Vitamin B1

• Helps convert carbohydrates into energy.

• Supports nerve function.

• Found in whole grains, pork, beans, nuts, and seeds.

Vitamin B2

• Helps break down proteins, fats, and carbohydrates for energy.

• Supports skin and eye health.

• Dairy products, eggs, green vegetables, lean meats.

• Deficiency results in cracked lips, sore throat, and sensitivity to light.

Vitamin B3 (Niacin)

• Helps in metabolism and energy production.

• Supports brain and nervous system function.

• Sources include meat, fish, whole grains, and peanuts.

• Deficiency results in pellagra (characterized by dermatitis, diarrhea, and dementia).

• Excess results in liver damage, flushing, and itching when taken in high doses.

Vitamin B5 (Pantothenic Acid)

• Functions:

  • Helps in the synthesis of coenzyme A, which is essential for fatty acid metabolism.

  • Supports energy production.

• Sources:

  • Found in nearly all foods, especially eggs, meats, and whole grains.

• Deficiency:

  • Extremely rare but may cause fatigue and irritability.

• Excess:

  • No major toxic effects.

Vitamin B6 (Pyridoxine)

• Functions:

  • Helps produce neurotransmitters like serotonin and dopamine.

  • Supports red blood cell production.

• Sources:

  • Bananas, potatoes, poultry, fish.

• Deficiency:

  • Depression, confusion, and anemia.

• Excess:

  • Nerve damage in very high doses.

Vitamin B7 (Biotin)

• Functions:

  • Helps convert food into energy.

  • Supports hair, skin, and nail health.

• Sources:

  • Egg yolks, nuts, whole grains.

• Deficiency:

  • Hair thinning, brittle nails, skin rashes.

• Excess:

  • No known toxicity.

Vitamin B9 (Folate/Folic Acid)

• Functions:

  • Essential for DNA synthesis and cell division.

  • Crucial for fetal development during pregnancy.

• Sources:

  • Leafy greens, legumes, citrus fruits.

• Deficiency:

  • Neural tube defects in newborns, anemia, and fatigue.

• Excess:

  • Can mask B12 deficiency symptoms.

Vitamin B12 (Cobalamin)

• Functions:

  • Essential for nerve function and red blood cell production.

  • Supports brain function.

• Sources:

  • Animal products like meat, dairy, eggs.

• Deficiency:

  • Pernicious anemia, nerve damage, fatigue.

• Excess:

  • No known toxicity.

Vitamin C (Ascorbic Acid)

• Functions:

  • Boosts the immune system.

  • Acts as an antioxidant and supports collagen formation.

• Sources:

  • Citrus fruits, strawberries, bell peppers.

• Deficiency:

  • Scurvy (causes bleeding gums, fatigue, and poor wound healing).

• Excess:

  • Can cause kidney stones and stomach upset in high doses.

Polyatomic Ion: An ionic compound with more than one atom.

Binary Molecular Compound: A compound composed of two elements

Binary Acid: Typically two elements

Oxyacid: Acid with an oxyanion

Identifying Compounds

Ionic compounds are usually a combination of a metal with a nonmetal.

Molecular compounds are usually made of nonmetals.

Naming Ionic Compounds

Nonmetals tend to gain electrons to get more stable while metals tend to lose electrons.

The Ionic compound must be in a form that results in neutrality.

Steps:

1. Name the cation first (metal or polyatomic cation)

2. Name the anion with -ide ending (or name the polyatomic anion)

Example:

NaCl = 0

Na = Cation Cl = Anion

NaCl = Sodium Chloride

(Group 1 and 2 metals can take on multiple changes (this makes naming more difficult))

For these types of compounds, we put a Roman numeral in parentheses after the metal. We place the numeral as its oxidation state.

There are four metals that we do not give a Roman numeral: Ag (Silver), Al (Aluminum), Cd (Cadmium), and Zn (Zinc).

There are also common names for the different oxidation states of the Roman numeral metals.

Example:

Copper (I) = Cuprous

Copper (II) = Cupric

Nuclear Chemistry: The study of changes to the nucleus of atoms.

Isotopes: Atoms of the same element that have different numbers of neutrons.

Transmutation: The change of one isotope or atom to another.

Radioactivity: The process of radioactive decay.

Half-Life: The time it takes for one-half of a radioactive sample to decay.

Ionizing Radiation: The release of energy that allows stability. (It is ionizing because it has the power to knock electrons out or add electrons to other atoms.)

Alpha Decay: A type of decay that releases an alpha particle

Beta Decay: A type of decay that only releases an electron.

Gamma Decay: A type of decay that only releases electromagnetic energy.

Excited State: The energy level of an electron that is higher and less stable.

Ground State: The lowest most stable energy level of an electron.

Spontaneous Fission: Radioactivity when an atom’s nucleus breaks in two.

Reactions happen due to the interaction of electrons. However, protons and neutrons can sometimes interact, releasing energy.

Any change to the number of protons will change an atom into a different one.

When the nucleus of an atom isn’t stable, protons and neutrons are released to reach stability.

Fun Fact: Carbon 14 is a radioactive isotope that is constantly renewed by cosmic rays in Earth’s atmosphere.

Radioactive decay occurs when a nucleus has more energy than a more stable version.

When decay occurs, ionizing radiation is released as the energy byproduct.

Types of Decay

1. Alpha Decay

The alpha particle is basically the same as a helium nucleus.

a Particle = Helium-4 Nucleus = ²₄He

The alpha particle is two protons and two neutrons.

Example: ²³⁸₉₂U to ²₄He + ²³⁴₉₀Th

2. Beta Decay

B Particle = Electrons = ⁰_-1e

Beta Decay has higher energy than alpha decay.

Example: ²³⁴₉₀Th to ⁰_-1e + ²³⁴₉₁Xe

3. Gamma Decay

Y = High-Frequency Electromagnetic Energy = ⁰₀Y

Gamma decay usually happens when electrons transition from an excited state to a ground state.

Gamma rays are the strongest of radiation.

Example: ⁶⁰₂₈Ni* to ⁰₀Y+ ⁶⁰₂₈Ni

Combustion Reaction: A reaction in which a reactant reacts with water and produces a high amount of energy as a result.

Synthesis Reaction: A reaction in which two or more reactants combine to form one compound.

Decomposition Reaction: A reaction in which a complex compound is broken into the components that created said compound.

Combustion Reaction

Combustion reactions usually involve burning and they release a lot of heat energy.

These types of reactions are good at making work and heat. They are commonly used for energy in cars, planes, and factories.

Example: Octane (C₈H₈) + Oxygen (O₂) = Carbon Dioxide (CO₂) + Water (H₂O). (Since the reaction is so hot, both the products are released as gases).

When carbon dioxide and water are products of a reaction, you can tell it is a combustion reaction.

Synthesis Reaction

Synthesis reactions are combination reactions. They end in one larger compound or thing being produced.

Example: Mg + O₂ = MgO₂

Decomposition Reaction

The type of reaction that breaks apart complex objects into less complex components. This is the reverse of a synthesis reaction.

Adding heat commonly breaks apart compounds.

Single replacement reaction

A + BC = AC + B •

Just as the name says, a single molecule from the same equation replaces another.

For the most part, metals tend to replace metals and nonmetals tend to replace nonmetals.

All "Single Replacement" reactions are "Redox Reactions".

Double Replacement Reaction

AB + CD = AD + BC similar to the Single replacement reaction; however, this one is double, and completely switches elements' places up.

Both of the reactants must be aqueous

When a double replacement happens between two aqueous solutions and the products all remain aqueous then no reaction takes place.

A "Double Replacement" reaction is NEVER a "Redox reaction"

Double Replacement reaction types:

- If a double replacement of two aqueous products happens and you find a solid in the product, then it's called a "Precipitation Reaction".

- If a double replacement happens between a strong acid and a strong base, it will produce water and salt and will be called "Acid-Base Neutralisation Reaction".

- If a double replacement of two aqueous products happens and you find a gas in the product, then it's called a "Gas Evolution Reaction".

Redox Reactions

Also called "oxidation-reduction reaction", is any chemical reaction in which the oxidation number of atoms changes. -Methane(CH4) is also called: Natural gas. -Almost all ionic compounds are considered salts.

Electromagnetic Radiation: A form of energy that exhibits wavelike behavior as it travels through space.

Electromagnetic Spectrum: All the forms of electromagnetic radiation.

Wavelength: The distance between corresponding points on adjacent waves (a distance unit).

Frequency: The number of waves that pass a given point in a specific time (usually one second) (It is expressed in waves per second, one wave/sec is called a hertz (Hz)).

Photoelectric Effect: The emission of electrons from a metal when light shines on the metal.

Quantum: The minimum quantity of energy that can be lost or gained by an atom.

Wave Description of Light

Visible light is a form of electromagnetic radiation. Other kinds include x-rays, ultraviolet, and infrared light.

All forms of electromagnetic radiation move at a constant speed of 3.00 x 10⁸ m/s through a vacuum and slightly slower through matter. (3.00 × 10^8 is also approximately the speed of light through air).

In electromagnetic radiation, the mathematical relationship between frequency and wavelength is written as follows:

c = ʎV

In this equation, c is the speed of light (in m/s), ʎ is the wavelength of the electromagnetic wave (in m), and V is the frequency of the electromagnetic wave (in s^-1). Because c is the same for all electromagnetic radiation, the product ʎV is a constant.

New Atomic Model

Fermion: Particles that make up the physical matter of the universe and are located to the left of the standard model.

Bosons: Particles that mediate how matter particles behave (force carriers or exchange particles)

Spin: A force of angular momentum in an angular motion (intrinsic angular momentum)

Conservation Laws of Particle Physics: The ways particles must interact with each other.

Pauli Exclusion Principle: Fermions can’t share the same quantum state.

Boson Statistics: The term given to describe the ability of bosons to take up the same quantum states.

Composite Bosons: Things that behave like bosons due to spin conservation.

Quarks: Particles that don’t exist on their own and carry an electric charge.

Baryon Number: The number of baryons in a particle.

Baryon: Any particle made of an odd number of three or more quarks (Example: Neutrons and Protons).

Anti-Particle: A particle that has the opposite values of a fundamental particle except for its mass.

Color Charge: A charge similar to the electric charge, but with three charge states.

Lepton Flavors: The different quantum numbers of each neutrino

• electron lepton number

• muon lepton number

• tau lepton number

Neutrino Chirality: The direction of their chirality which is left.

The Standard Model shows all the discovered fundamental particles.

The main difference between bosons and fermions is their spin.

Fermions have a spin of ½ while bosons have a spin of 1 (0 in the case of the Higgs boson)

Conservation Laws

The spin must be conserved. In particle interactions, spin will always remain constant.

Energy and linear motion are the most fundamental conservation laws.

Fermions in a group obey the Pauli Exclusion Principle

Bosons are opposite as they can take on the same quantum state.

Bosons are anything with a spin of a whole integer.

Fermions are anything with a spin of a decimal integer

Fermions

Fermions are split into two categories, quarks and leptons.

Quarks;

Up and down Quarks make up neutrons and protons. The resulting charges of the particles are the sum of the fundamental quark charges.

Up = 2/3

Charm = 2/3

Top = 2/3

Down = -1/3

Strange = -1/3

Bottom = -1/3

Quarks interact with all of the forces. They are also the only particles that feel the strong nuclear force.

All quarks and gluons have a color charge. Quarks are restricted from coming together unless they have color charges that result in a color-neutral particle.

Leptons;

Electrons are the best leptons as they are responsible for chemical reactions and electricity.

Leptons are made up of two groups, the neutrinos and the charged leptons.

Neutrino Properties

Neutrinos only interact with the weak force and barely interact with matter.

Neutrinos have a very small mass greater than zero and all their masses combine to 0.3 cV.

Neutrinos can change between lepton flavors.

Neutrinos have only been observed to only be left-handed. Anti-Neutrinos are only right-handed.

Dark Matter: A hypothetical substance that makes up most of the matter in galaxies.

Axion: Subatomic particles that have not been discovered but have properties of dark matter.

Dark Energy: A theoretical force that repulses all matter in the universe and counteracts gravity.

The universe as we know it is only made up of 5% atoms and molecules. Another 25% of the universe is made up of dark matter. The rest 70% is made up of dark energy.

Dark matter affects the gravitational pull of galaxies, as we theorized. Scientists observed a constant orbit speed throughout multiple galaxies, which contradicts the theories of gravity. Therefore, a theoretical substance that could not be observed, dark matter, was hypothesized.

Huygens Principle: A principle that states that you can predict the position of a wave in the future by looking at its current position.

Diffraction: The process in which waves are re-shaped by obstacles.

Double Slit Experiment: An experiment to see if light was a particle or a wave.

Intensity: The energy transported by the light over time or its brightness.

1 = (energy/time)/area = power/area

Is light a wave or a particle?

In early physics, light was believed to be a particle. Now, we know that light is both a wave and a particle.

r=vt

Waves behave in a set of ways that allow us to observe them. All waves follow the Huygens Principle, but when an object interferes, the wavelets are changed.

Particles move straight meaning that they don’t end up behind the object.

Double Slit Experiment

A window was opened with a double-sided slit behind it. Behind that slit was two more slits. If light were a particle, there would be two bright spots.

Instead, there were multiple lines on the screen. This meant that light was a wave.

The diffraction pattern was created by the light interference. In slit experiments where the slits were an exact wavelength apart and have constructive interference. If they were not, they would interfere destructively.

Path Difference Equation

d x sinO = p

P equals the distance of each slit multiplied by the angle’s sine between the screens point and the straight line between the slits and the screen.

Light with more energy has a shorter wavelength (more on the blue side), while light with less energy has a longer wavelength (on the redder side).

Depending on the angle, different rays travel different distances. Depending on how they line up, the rays interact constructively or destructively.

With a total path difference of a full wavelength, for each light ray, there’s a corresponding light ray that’s shifted by half a wavelength. This causes destructive interference of the two rays.

Kinematics: The study of motion without considering the forces causing it.

Average speed considers total distance over time, while average velocity focuses on displacement over time.

Acceleration measures the rate of change in velocity. Constant velocity implies zero acceleration.

Projectile motion exhibits a parabolic trajectory due to the independent horizontal and vertical components of motion.

Horizontal motion: The motion of the object in the x direction is constant and is not affected by gravity.

Vertical motion: The motion of the object in the y direction is affected by gravity and follows a parabolic path.

Free fall signifies motion under the sole influence of gravity, with all objects experiencing the same acceleration regardless of mass.

Terminal velocity marks the maximum speed an object attains during free fall due to air resistance.

Kinematics involves analyzing distance, displacement, speed, velocity, and acceleration. Importantly, while distance is the total path length, displacement focuses solely on the change in position. Similarly, speed is scalar, representing the rate of distance covered, while velocity is a vector encompassing both the rate and direction of displacement.

Important Equations of Kinematics

• v = u + at (velocity-time)

• s = ut + 1/2at^2 (displacement-time)

• v^2 = u^2 + 2as (velocity-displacement)

• s = vt - 1/2at^2 (displacement-velocity)

• Where:

• u = initial velocity

• v = final velocity

• a = acceleration

• s = displacement

• t = time

These are equations that describe movement in one and two dimensions where acceleration is constant.

Two Dimensional Motion

In 2-D, project motion is introduced. Gravity

System: A section of the universe that you happen to be talking about at a certain time.

Work: The force applied to a system for a certain distance.

Power:

Energy: The ability to do work.

Kinetic Energy: The energy of motion

Potential Energy: Energy that could be used to do work.

Work

If you wanted to pull a box, your pulling would be the force and the box would be the system. The amount of work you did to pull the box would be the force times the distance the box moved.

If the force put in is 50N

And the distance traveled was 5m

Then the work would be 250J

If the example included a force that was not in the same direction as the movement of the box, we would calculate a little differently. In an instance where the rope pulling the box was higher than the box, the force would be an angle to the box. To calculate the work, we would multiply the distance by the cos0.

Thus W = F(d)(cos0)

To find the work done by varying distances in a case where the force is not constant, you must integrate the force relative to the distance the object moved.

Thus in this case W = ∫ F(x)dx (assuming force is parallel to distance moved)

Work can be thought of as the change of energy.

Kinetic and Potential Energy

Kinetic energy is activated when work is applied

KE = 1/2m v²

Potential energy is the possible work that can be applied.

The most common example of potential energy is gravitational potential energy. When an object falls, gravity does work on the object and pulls it down. Once it reaches the ground, however, its gravitational potential energy is zero.

PE_gravity