B1: Biology – Cells and Organs, for the T Level Health

B1 – Cells and Organs (T Level Health – Core Science)

B1.1: Cells – Structure and Function

Types of Cells:

Cell Type	Description	Example
Animal cells	Cells in humans and animals	Skin cells, nerve cells
Specialised cells	Cells with specific roles determined by gene expression	Red blood cells, sperm cells, epithelial

Basic Structures in Animal Cells:

Structure	Function	Details
Nucleus	Contains DNA and controls the cell	Contains chromatin; the nucleolus is where ribosomes are synthesized
Cytoplasm	Where chemical reactions happen	Gel-like substance containing organelles and enzymes
Cell membrane	Controls what goes in and out	Selectively permeable lipid bilayer with proteins
Mitochondria	Releases energy from respiration	Site of aerobic respiration; contains its own DNA
Ribosomes	Where proteins are made	Can be free in cytoplasm or attached to the endoplasmic reticulum

B1.2: Cell Specialisation

Specialised Cells and Functions:

Cell	Adaptation	Function	Details
Red blood cell	No nucleus, biconcave shape, lots of hemoglobin	Carries oxygen	Increased surface area for oxygen diffusion; hemoglobin binds to oxygen
Nerve cell	Long with branches, myelin sheath	Sends messages (impulses)	Insulating myelin sheath for faster impulse transmission; synapses for cell communication
Muscle cell	Lots of mitochondria, can contract	Movement	Muscle fibers contain actin and myosin; mitochondria provide ATP for contraction
Sperm cell	Tail for movement, enzymes in head	Fertilises the egg	Flagellum for motility; acrosome contains enzymes to penetrate the egg
Ciliated cell	Tiny hairs (cilia) to move mucus	Keeps airways clear	Cilia beat in coordinated motion to move mucus and trapped particles

B1.3: Tissues, Organs, and Systems

Tissues:

Group of similar cells working together

e.g. muscle tissue (for movement), epithelial tissue (lining organs), Connective tissue (provides support), Nervous tissue (transmits signals)

Organs:

Made from different tissues working together

e.g. heart (muscle, nerve, blood tissue), Lungs (Epithelial, connective, and muscle tissues)

Systems:

Organs that work together for a function

e.g. respiratory system (lungs, trachea), digestive system (stomach, intestines), cardiovascular system (heart, blood vessels, blood)

B1.4: Human Organ Systems (Overview)

System	Main Organs	Function	Details
Respiratory	Lungs, trachea, diaphragm	Breathing and gas exchange	Lungs facilitate the exchange of oxygen and carbon dioxide between the air and the bloodstream. The trachea, or windpipe, allows air to pass from the nose and mouth into the lungs. The diaphragm is a muscle that contracts and relaxes to assist the lungs in drawing air in and expelling carbon dioxide out.
Circulatory	Heart, blood vessels, blood	Transport oxygen, nutrients, waste	The heart is the main organ responsible for pumping blood throughout the body. Blood vessels, including arteries, veins, and capillaries, form a network that carries blood from the heart to the body's tissues and back. Blood is composed of plasma, red blood cells, white blood cells, and platelets, which transport oxygen, nutrients, hormones, and waste products.
Digestive	Stomach, intestines, liver	Break down food and absorb nutrients	The stomach is a muscular organ that churns and mixes food with digestive juices. The intestines, which include the small and large intestines, are responsible for absorbing nutrients from digested food and eliminating waste products. The liver produces bile, which helps break down fats, and also filters toxins from the blood.
Nervous	Brain, spinal cord, nerves	Send and receive messages	The brain is the control center of the body, responsible for thoughts, memory, and emotions. The spinal cord relays messages between the brain and the body. Nerves transmit electrical and chemical signals throughout the body, allowing the body to respond to stimuli.
Urinary	Kidneys, bladder, urethra	Remove waste and control water balance	The kidneys filter waste products from the blood and produce urine. The bladder stores urine until it is eliminated from the body through the urethra. This system regulates fluid balance, electrolyte levels, and blood pressure.
Musculoskeletal	Muscles and bones	Movement and support	Muscles contract and relax to produce movement. Bones provide structure and support for the body, protect internal organs, and store minerals. The interface of the muscles and bones allow for a wide array of movements, from walking to writing.

B1.5: DNA, Chromosomes and Genes (Intro only)

(Light overview – full genetics comes later)

DNA: Genetic material found in the nucleus, contains all the genetic information for the organism.
Chromosomes: Long strands of DNA (humans have 46), organized structures that carry genetic information.
Genes: Small sections of DNA controlling characteristics (e.g. eye colour, blood type), the basic unit of heredity.

B1.6: Cell Division (Intro level)

Mitosis: Cells make exact copies:
Growth
Repair
Asexual reproduction
Outcome: 2 identical daughter cells
Meiosis: Cell division that produces gametes (sex cells)
Outcome: 4 genetically different haploid cells

B1.7: Importance in Health

Knowing how cells and organs work helps:
Understand diseases
Give better treatment
Monitor body systems (e.g. breathing, pulse)
Health conditions often affect specific organs or cell types (e.g. sickle cell anaemia, lung disease)
Cell malfunctions can cause diseases such as cancer

Quick Summary for Revision:

Animal cells have nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
Specialised cells = adapted for their function

Absolutely! Here's everything you need to know for B1: Biology – Cells and Organs from the T Level Health – Core Year 1 content, clearly organised and exam-focused so you can revise efficiently.

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# 🧬 B1: Cells and Organs (Complete Notes – Exam Ready)

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## 🔬 B1.1: Structure and Function of Cells

### 🔍 Basic Animal Cell Structures:

| Structure | Function |

| ----------------- | ------------------------------------------ |

| Nucleus | Contains DNA, controls cell activities |

| Cytoplasm | Site of chemical reactions |

| Cell membrane | Controls what enters and leaves the cell |

| Mitochondria | Site of respiration, produces energy (ATP) |

| Ribosomes | Makes proteins |

> ✅ Only animal cells for T Level Health – no plant cells needed.

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## 🧬 B1.2: Specialised Cells

### 🔧 Cells Adapted for a Function:

| Cell | Adaptations | Function |

| ------------------ | ---------------------------------------- | -------------------------- |

| Red blood cell | No nucleus, biconcave shape, haemoglobin | Carries oxygen |

| Nerve cell | Long axon, branches | Sends electrical impulses |

| Muscle cell | Long, contracts, many mitochondria | Allows movement |

| Sperm cell | Tail for swimming, enzymes in head | Fertilises egg |

| Ciliated cell | Tiny hair-like cilia | Moves mucus out of airways |

> 🔑 Key idea: Structure fits function (form = job)

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## 🧵 B1.3: Tissues, Organs, and Systems

### 🧪 Definitions:

* Tissue: Group of similar cells working together (e.g. muscle tissue)

* Organ: Made of different tissues performing a function (e.g. heart)

* Organ system: Group of organs working together (e.g. circulatory system)

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## 🫁 B1.4: Major Human Organ Systems

| System | Main Organs | Function |

| ------------------- | --------------------------- | --------------------------------------- |

| Respiratory | Lungs, trachea, diaphragm | Gas exchange – oxygen in, CO₂ out |

| Circulatory | Heart, blood vessels, blood | Transport oxygen, nutrients, waste |

| Digestive | Stomach, intestines, liver | Break down food, absorb nutrients |

| Nervous | Brain, spinal cord, nerves | Send and receive signals |

| Urinary | Kidneys, bladder, urethra | Remove waste, control water/salt levels |

| Musculoskeletal | Bones, muscles, joints | Support, posture, movement |

> ⚠ You must know the organs in each system and what each system does.

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## 🧬 B1.5: DNA, Genes and Chromosomes (Basic Overview)

* DNA = Genetic material inside the nucleus

* Gene = Small section of DNA controlling a characteristic

* Chromosome = Long strand of DNA (humans have 46, or 23 pairs)

* Genes control:

* Physical traits (e.g. eye colour)

* Cell functions (e.g. insulin production)

> 🧠 Not full genetics yet, just know that DNA → genes → proteins.

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## 🔁 B1.6: Cell Division (Mitosis)

### 🔄 Mitosis:

* Type of cell division for:

* Growth

* Repair

* Replacing dead cells

Produces *2 identical daughter cells** (same DNA)

* Happens in all body (somatic) cells

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## 🧼 B1.7: Relevance to Health

### Why You Need to Know This:

* Understanding cells and systems helps with:

* Diagnosing illnesses

* Monitoring body systems (e.g. pulse, breathing)

* Understanding how diseases affect organs/cells

* Providing effective person-centred care

> ✅ Helps with roles like nurses, HCAs, therapists – everything starts with the cells!

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## 📌 Quick Recap for Exam

* Animal cells: nucleus, membrane, cytoplasm, mitochondria, ribosomes

* Specialised cells = structure fits function

* Tissues → Organs → Organ systems

* Know 6 main body systems: respiratory, circulatory, digestive, nervous, urinary, musculoskeletal

* Mitosis = identical cells for growth and repair

* DNA = carries genes → control characteristics and protein-making

* All knowledge connects to healthcare roles

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