Gr.10 LIFE SCIENCES Remote learning booklet terms 1 - 4.docx

REMOTE LEARNING ACTIVITY BOOK (RELAB)

Subject: LIFE SCIENCES
Grade: 10
Terms One - Four

TABLE OF CONTENTS

TERM 1

• Week 1: How science works
• Week 2: Biosphere and Biomes
• Week 3: Environment and Ecosystems
• Week 4: Abiotic and biotic factors
• Week 5: Energy flow
• Week 6: Water and Oxygen cycles
• Week 7: Carbon and Nitrogen cycles
• Week 8 & 9: Classification schemes and Main groupings

TERM 2

• Week 1: History of life on Earth: Life’s history, The three eras & Geological timescales
• Week 2: History of life on Earth: Cambrian explosion
• Week 3: History of life on Earth: Mass extinctions
• Week 4: History of life on Earth: Fossil formation and methods of dating
• Week 5: The chemistry of life: Molecules for life: Organic molecules and Minerals
• Week 6: The chemistry of life: Organic compounds (Carbohydrates & Lipids)
• Week 7: The chemistry of life: Organic compounds (Proteins, Enzymes, Nucleic acids & Vitamins)
• Week 8: Cells: The basic unit of life: (Cell wall, cell membrane, nucleus & cytoplasm)
• Week 9: Cells: The basic unit of life: (Mitochondria, Ribosome, Endoplasmic reticulum & Golgi-body)
• Week 10: Cells: The basic unit of life: (Plastids, Vacuoles & difference between plant and animal cells)

TERM 3

• Week 1 & 2: Cell division: mitosis
• Week 3: Animal tissues
• Week 4 & 5: Plant tissues and Organs: Anatomy of dicotyledonous plants
• Week 6: Support and transport systems in plants: The leaf
• Week 7: Support and transport systems in plants: Transpiration
• Week 8: Support and transport systems in plants: Water uptake, Transport of water & Translocation of manufactured food
• Week 9 & 10: Support system in animals: Human skeleton and Functions of the skeleton

TERM 4

• Week 1: Transport systems: Blood circulation system
• Week 2: Transport systems: Direction of blood flow & Lungs and pulmonary system

INTRODUCTION AND PURPOSE OF THE RELAB

The RELAB is a strategy for remote learning due to rotational timetables caused by the pandemic. It aligns with:

• GDE Strategic goal 2: promoting quality education.
• DBE Circular S13 of 2020: supporting the Recovery Annual Teaching Plan (RATP).
• GDE Circular 11 of 2020: providing Learning Activity Packs.

RELAB provides learning resources for learners without devices or data for online learning. The content is briefly explained with related concepts as revision. It includes notes, mind-maps, concept progression, exemplar exercises, and practice problems pitched at different cognitive levels. The exercises are designed to help learners analyze questions effectively, addressing failures identified in NSC diagnostic reports. Learners complete exercises at home and receive feedback at school, with teachers marking work and providing necessary remediation and intervention. Educators are encouraged to use WhatsApp groups for reminders. Curriculum coverage should be simultaneous, with feedback confirming RELAB material usage, preparing learners for formal assessment.

WEEK 1: TOPIC: Orientation to Life Sciences

SUB-TOPIC: How science works

GRAPHS

Graphs record the relationship between two variables in picture form, making it easier to interpret trends. Common types include line, bar, histograms and pie graphs.

• Axis: Vertical (y-axis), horizontal (x-axis).
• Origin: Where x- and y-axes cross, MUST have a zero.
• Independent variable: x-axis, controlled/changed by the experimenter.
• Dependent variable: y-axis, changes in response to the independent variable.
• Scale: How information is plotted, must cover all figures and be constant (e.g., 5, 10, 15).
• Heading: Includes information on both axes and graph type (underlined, no units).
• Labels: Correctly labelled axes with units.
• Plotting points: Clear dots, joined with a ruler.

BAR GRAPHS

Used when one variable is given in numbers.

• Separate bars, like in a prison.
• Bars are the same width measured with ruler.
• Spaces between bars are the same size.
• No bars against the y-axis.
• Clearly marked scale with numbers.
• Use a key (e.g., A, B, C).
• Do not write in the bars.

HISTOGRAMS

Used for continuous groups of information, similar to bar graphs but with no spaces between the bars.

• Bars are the same width.
• Clearly marked scale.
• Use a key.
• Do not write in the bars.

PIE CHARTS

1. Add the numbers to get a total.
2. Convert to percentage: \frac{value}{total} \times 100.
3. Convert percentage to degrees: percentage \times 3.6 or \frac{360}{100}.
   Example:
   Lipids: 10 portions
   Proteins: 20 portions
   Carbohydrates: 40 portions

Total portions: 10 + 20 + 40 = 70

Lipids: \frac{10}{70} \times 100 = 14\%%
Proteins: \frac{20}{70} \times 100 = 29\%%
Carbohydrates: \frac{40}{70} \times 100 = 57\%%

Convert percentages to degrees:

Lipids: 14 \%% \times 3.6 = 50^o
Proteins: 29 \%% \times 3.6 = 105^o
Carbohydrates: 57 \times 3.6 = 205^o

Remember to use a key and do not write numbers in a pie chart.

SCIENTIFIC DIAGRAMS

1. Drawn with a pencil.
2. Sharp, clear, solid lines.
3. No shading or colour.
4. Large size (10 lines or third of page).
5. Labels printed in lowercase unless of a person (e.g. Golgi apparatus).
6. Labels one below the other.
7. Parallel label lines with a ruler.
8. Heading: Drawing of … what it is … which view … fresh material/microscope … magnification.
9. Underlined heading.
10. Annotated diagrams: labels and functions/descriptions of structures.

TABLES

1. Heading with variables (underlined).
2. Columns and rows (horizontal and vertical lines).
3. Column headings with units (if applicable).
4. Frame/border drawn with a ruler and pencil.

THE SCIENTIFIC METHOD

1. Ask a question: How, Why, When, What, or Where?
2. Construct a hypothesis: An educated guess: "If (I do this), then (this) will happen."
   • Measurable, testable, includes dependent and independent variables.
3. Test your hypothesis by doing an experiment:
   • Fair test: change only one factor.
   • Repeat experiments if possible.

Variables

• Independent variable: Controlled by the experimenter.
• Dependent variable: Measured in the experiment.
• Fixed variables: Stay the same throughout the experiment.

Experiment Components

• Aim: To determine/investigate (includes variables).
• Apparatus: List all equipment/chemicals.
• Method: Numbered steps, short, simple, third person.
• Results/Observation: Table to record results, includes what you've seen, heard, or smelt. May include a graph.
• Discussion: State results, explain why it happened, was hypothesis true/false, was it a fair test, and how to improve.
• Conclusion: Short statement referring back to aim.

Reliability

• Repeat the investigation.
• Increase the sample size.

Validity

• Control all factors except the one being tested.
• Samples must be chosen randomly.

Calculations

1. Averages: Add quantities and divide by the number of quantities: \frac{2+4+6+8}{4} = 5
2. Percentage Increase/Decrease: \% increase\/decrease = \frac{difference}{first} \times 100
3. Ratios: Simplify to the simplest form, consider the order of ratio. Remember that the order of the ratio is given in the question.
4. Magnification:
   • Total magnification = eyepiece magnification x objective lens magnification = 10 \times 40 = 400X
   • Actual length of specimen = \frac{measured \ length \ of \ specimen \times length \ on \ scale}{measured \ length \ on \ scale}

WEEK 2: TOPIC: Biosphere to ecosystems

SUB-TOPIC: Biosphere & Biomes

BIOSPHERE

The biosphere is a global ecosystem composed of living organisms (biota) and nonliving factors (abiotic) from which they derive energy and nutrients. It consists of three components: Atmosphere, Lithosphere and Hydrosphere.

ATMOSPHERE

The layer of gases surrounding the earth, absorbing ultraviolet rays to allow life.

LITHOSPHERE

The rocky outer part of the Earth, consisting of the brittle crust and top part of the upper mantle. The lithosphere shields living organisms from the heat of the Earth’s core and contains ionic compounds.

HYDROSPHERE

The combined mass of water on, under, and above the Earth's surface (lakes, rivers, oceans). It is home to a wide diversity of aquatic plant and animal life.

Interaction Among Spheres

Disturbances in one sphere affect the others. For example, deforestation (biosphere) leads to soil erosion (lithosphere) into rivers (hydrosphere) and an increase in atmospheric carbon dioxide (atmosphere). The spheres are closely connected.

BIOMES

The biosphere is divided into biomes, collections of plants and animals with common characteristics. Biomes have distinct biological communities formed in response to a shared physical climate defined by temperature range, soil type, and light/water availability.

Types of Biomes

1. Terrestrial Biomes: Land areas with similar climates and plant communities (trees, shrubs, grasses, and animals).
2. Aquatic Biomes: Divided into freshwater and marine regions.

South African Terrestrial Biomes

South Africa has nine biomes based on vegetation types:

1. Grassland.
2. Savannah.
3. Arid Savannah.
4. Succulent Karoo.
5. Nama Karoo.
6. Forest.
7. Fynbos.
8. Desert.
9. Thicket.

Influence of Climate, Soils and Vegetation on Organisms

Climate (annual precipitation and temperature) determines plant, animal, and soil organism communities in a biome. Climate affects soil, and vegetation can affect climate and weather patterns through water vapor release during photosynthesis.

Aquatic Biomes

Water covers a major portion of the Earth’s surface, so aquatic biomes contain a rich diversity of plants and animals. It's divided into Freshwater and Marine sub biomes.

WEEK 3: TOPIC: Biosphere to ecosystems

SUB-TOPIC: Environment and Ecosystems

Environment

Encompasses the interaction of all living species, climate, weather and natural resources that affect human survival and economic activity. Human activities can be detrimental (atmospheric pollution, global warming, biodiversity destruction) or beneficial (preservation of natural resources).

Ecosystem

A community of biotic (living) and abiotic (non-living) factors in an area that interact with each other. Biotic factors include plants, animals, and microorganisms. Abiotic factors include soil, water, temperature, and sunlight. Ecology is the study of all the relationships in an ecosystem.

WEEK 4: TOPIC: Biosphere to ecosystems

SUB-TOPIC: Biotic and Abiotic factors

ABIOTIC FACTORS

Physiographic Factors

The physical geography of an area, including aspect, slope, and altitude.

• Aspect: Direction an area faces relative to the sun. In South Africa, north-facing slopes are hotter and drier, while south-facing slopes are cooler and moister.
• Slope: Steepness of the land. Steeper slopes have faster water flow, more erosion, thinner soil, and support smaller plants. Gradual slopes have less erosion.
• Altitude: Height above sea level. Higher altitudes have decreased atmospheric pressure, oxygen content, and temperature. Rainfall and wind speeds are greater, and frost/snow occur.

SOIL (EDAPHIC) FACTORS

Soil provides water and minerals for plant growth. Soil characteristcs include: pH, humus content, texture (sand, loam, clay), air content, and water retention capacity.

• pH: Acidity or alkalinity.
• Humus content: Organic component from decomposed matter, increasing fertility.
• Texture: Determined by particle size (sand: large, loam: mix, clay: small).
• Air content: Spaces between particles (sand > loam > clay).
• Water retention capacity: Sandy (low) < Loamy (moderate) < Clay (high).

Light

Plants grow where there is enough light for photosynthesis (sun plants vs. shade plants).

Temperature

Temperature distribution changes from the equator to the poles due to the decrease in temperature and rainfall further away from the equator.

Water

Essential for life (70% of living things). Chemical reactions occur in water and water transports substances, and maintains stable body temperatures. Wetlands are essential ecosystems.

• Wetlands act as natural filters.
• They slow down floodwaters.
• Wetlands are rich in plant life.

Atmospheric gases

• Composition: 78% Nitrogen, 21% Oxygen, 0.04% Carbon dioxide, and water vapor.
• Oxygen is needed for respiration, and carbon dioxide is needed for photosynthesis.
• The greenhouse effect traps sun's heat (water vapor, carbon dioxide, methane are greenhouse gases).

Wind

Moving air. Wind is greater at high altitudes.

BIOTIC FACTORS

Plants, animals, fungi, lichens, and microorganisms.

• Producers: Autotrophs that make their own food through photosynthesis.
• Consumers: Heterotrophs that feed on other organisms.
  • Carnivores: Feed on animals.
  • Herbivores: Feed on plants.
  • Omnivores: Feed on both plants and animals.
• Decomposers: Feed on dead organic matter, releasing substances back into the environment.

WEEK 5: BIOSPHERE TO ECOSYSTEMS

SUB-TOPIC: ENERGY FLOW

Energy Flow in Ecosystems

Energy in Earth's ecosystems originates from the Sun. Energy is distributed through food chains and food webs. Living organisms occur at different trophic levels, those are feeding levels.

• Producers (Autotrophs): Living organisms (green plants) produce their own food and form the first trophic level. They have the greatest amount of energy.
• Consumers (Heterotrophs): Living organisms that cannot produce their own food, they feed on other organisms.
  • Primary consumers: Herbivores, occupy the 2nd trophic level.
  • Secondary consumers: Carnivores or omnivores, occupy the 3rd trophic level.
  • Tertiary consumers: Carnivores or Omnivores, occupy the 4th trophic level.
• Decomposers (Saprophytes): Organisms that break down dead organic material and wastes like bacteria and fungi.

Energy is used by the organisms at each trophic level for growth or lost as heat through respiration or in urine and feces.

Ecological Pyramids

An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. Types of ecological pyramids are:

• Energy pyramid: shows relative amounts of energy available at different trophic levels.
• Biomass pyramid: shows the total mass of the organisms at each trophic level.
• Number pyramid: shows total number of organisms at each trophic level.

WEEK 6: TOPIC: Biosphere to ecosystems

SUB-TOPIC: CYCLES (Water and Oxygen)

The water and oxygen cycle

The following terms will help you understand cycles:

• Condensation: Change of water from gaseous into liquid form.
• Precipitation: Water moves from the atmosphere to earth in the form of rain, mist, hail, dew, and snow.
• Infiltration: Water infiltrates deep into the soil to create the water-table
• Evaporation: The process of turning from liquid into vapor.
• Transpiration: Loss of water vapor through the stomata of the leaves.
• Atmosphere: The air surrounding the earth’s surface.
• Respiration: The chemical process whereby energy-rich molecules, example, glucose, is chemically broken down to release energy.
• Photosynthesis: The process whereby plants absorb CO2 and in turn release O2
• Combustion: Reaction of a substance with oxygen as in burning.

Cycles reuse water and oxygen over and over again.

The Water Cycle

Water moves through organisms and the environment by:

• Precipitation, distribution, and absorption.
• Evaporation and condensation.

Continuous movement of water within the Earth and atmosphere, it includes many different processes. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow.

The Oxygen Cycle

Oxygen is essential for cellular respiration, which is used in the breakdown of glucose to release energy. Normal concentration of \text{O}2 in the atmosphere is approximately 21%. Some of this \text{O}2 dissolves in the waters of ponds, lakes, dams, rivers and the oceans.

WEEK 7: TOPIC: Biosphere to ecosystems

SUB-TOPIC: CYCLES (Carbon and Nitrogen)

Carbon Cycle

The carbon cycle involves:

1. Photosynthesis: Carbon is absorbed by plants and turned into carbohydrates, proteins and fats.
2. Feeding: Carbon passes from plants to animals during feeding, and is turned into carbohydrates, proteins and fats in the animal’s body.
3. Death and decay: Carbon passes from plants and animals to decompose organisms and turn the carbon into decomposer carbohydrates, proteins and fats.
4. Respiration: when plants and animals die, the decomposers breakdown these bodies and release carbon in the form of carbon dioxide back into the atmosphere, water or soil.
5. Compaction: sometimes the dead plants and animals do not break down and the carbon becomes locked in for long period.

Nitrogen Cycle

The nitrogen cycle involves nitrogen fixation, nitrogen assimilation, ammonification, nitrification, and denitrification.

WEEK 8 & 9: TOPIC: Biodiversity and classification

SUB-TOPIC: Classification schemes: a way of organizing biodiversity Main groupings

Classification

Classification is the grouping and sorting of things according to similarities and differences. Life forms are put into groups as a result of classification. This makes it easier for the scientist to study these life forms.

Taxonomy

Taxonomy is the science of naming and classifying a wide range of living things, and it refers to the science of naming and classifying a wide range of living things. Living things were classified into two groups: plants and animals, and more advanced classification systems have been made.

The Five Kingdom System

Developed by Robert H. Whittaker in 1969 with living organisms placed into 5 kingdoms (Monera, Protista, Fungi, Plantae, Animalia) based on characteristics of:

• cell structure and cell specialization
• mode of nutrition
• reproduction and evolutionary history

Terminology:

• Taxonomy is the branch of biology that classifies all living things. It was developed by the Swedish botanist Carolus Linnaeus, and his system of classification is still used today.
• Linnaeus and other scientists used Latin because it was a dead language- meaning nobody spoke it anymore. Hence, it is a neutral language, and the scientific name can be used to avoid confusion with common names.
• Eukaryotes: A true nucleus enclosed by a nuclear membrane. Organisms that possess true nuclei are called eukaryotes..
• Prokaryotes: Organisms with nuclear material not enclosed by membranes are called prokaryotes.
• Autotrophic organisms: Organisms that can manufacture their own food.
• Heterotrophic organisms: Organisms that cannot manufacture their own food.
• Saprophytes: Organisms that feed on dead and decaying matter.
• Unicellular: Organisms that are made up of one cell only.
• Multicellular: Organisms that are made up of many cells.

Binomial Nomenclature

Linnaeus invented binomial nomenclature, the system of giving each type of organism a genus and species name. He also developed a classification system called the taxonomic hierarchy, which has seven ranks from general to specific: kingdom, phylum, class, order, family, genus, and species. Genus and species are always typed in italics and underlined when it is handwritten. The Genus name will be written with a capital letter while the species name is written with a small letter Example of taxonomic classification: Remember this sentence: “King Philip Came Over For Good Spaghetti”

Taxonomic Keys

1. Pictorial: Illustrations (pictures, photographs), and identified by comparing to illustrations.
2. Verbal: Statements or questions of characteristics.

WEEK 10: TOPIC: Cells: The basic unit of life

SUB-TOPIC: Plastids, Vacuoles & difference between plant and animal cells

Plastids

Plastids are double membrane-bounded and are found only in plant cells. There are 3 types of plastids: chloroplast, leucoplast and chromoplast.

Chloroplast

The chloroplast is made up of a gelatinous substance called the stroma that contains many enzymes that are essential for photosynthesis. the stroma is surrounded by a double membrane suspended in the stroma are thylakoids. These are stacks of membrane-like structures; each stack is called a granum. Chlorophyl and other photosynthetic pigments are located in the thylakoids, which are the site of photosynthesis.

Types of Plastids & Functions

• Chloroplasts are responsible for photosynthesis and contains the green pigment chlorophyl.
• Leucoplasts are colorless and store starch.
• Chromoplasts contain pigments, and give fruit, vegetables and flowers their color. Carotenoid-containing chromoplasts can be red, orange or yellow.

Vacuoles

Each plant cell usually has one large vacuole. Vacuoles are fluid-filled organelles that occur in the cytoplasm of most plant cells. A selectively permeable single membrane, the tonoplast, surrounds the vacuole. the vacuole contains cell sap, which is a liquid that consists of water, mineral salts, sugars and amino acids. It Plays a role in the digestion and excretion of cellular waste.

Plant and Animal cell differences:

TERM 2

WEEK 1: TOPIC: History of life on earth

SUB-TOPIC: Life’s history, The three eras & Geological timescales

History of life on Earth

Life on Earth started approximately 3,500 million years ago. The pyramids were built 4500 \text{ years} ago, dinosaurs die out 65 million \text{ years} ago, Human recorded history stretches back only 10, 000 \text{ years}.

Geological Timescale

The Earth’s history has been divided into a series of time intervals called the Geological Timescale, the divisions vary in length according to significant events in the history of the Earth into eras, periods and epochs in years, months, days or hours.. Geologists have divided the Earth’s history into eras, periods and epochs. These time intervals vary in length according to significant events in the history of the Earth. They are not equal divisions of time like years, months, days or hours.

• Eons: Longest time periods (hundreds of millions of years).
• Eras: Smaller time periods divided into Eons.
• Periods: Varying numbers of periods of different lengths of time.

History includes prokaryotes, oxygen accumulation, eukaryotic fossils, animal fossils, Cambrian explosion.

WEEK 2: TOPIC: History of life on earth

SUB-TOPIC: Cambrian explosion

The Cambrian Explosion is a relatively short period of time marking the origins of early forms of all animal groups. It is when there was a sudden appearance of the major groups of animals. From the end of the Cambrian period to the Holocene epoch, the fossil record shows the evolution from the Cambrian forms such as:

• fish: about 438 million years ago
• amphibians: about 380 million years ago
• reptiles: about 225 million years ago
• birds: about 180 million years ago
• mammals: about 150 million years ago
• humans: about 250 000 to 300 000 thousand years ago.

WEEK 3: TOPIC: History of life on earth

SUB-TOPIC: Mass extinctions

MASS EXTINCTIONS

There were five major mass extinction events:

• Ordovician: Climate changes, trilobites extinct.
• Devonian: Ice ages, global cooling.
• Permian: Volcanic eruptions, reptiles and frogs died.
• Triassic: Acid rain, oxygen drop in water.
• Cretaceous: Asteroid impact, dinosaur extinction.

A sixth mass extinction is at hand due to human activities.

Causes of mass extinctions are Environmental disasters and Organisms failing to adapt to habitat or environmental changes:

WEEK 4: TOPIC: History of life on earth

SUB-TOPIC: Fossil formation and Methods of dating

TERMINOLOGY

• Fossil: The remains or trace of an organism that lived a long time ago and has been preserved in rock.
• Paleontologist: person who interested in uncovering the history of the Earth by studying fossils
• Paleoanthropologist: specializes in studying human ancestors.
• Petrification: The process by which the remains of organisms are replaced by silica or calcium and turned into stone
• Sedimentary rock: Rock formed from layers of mud, sand, salt, pebbles, or carbonate in a river, lake, sea, desert
• Transitional: In between, a stage between one form and another.

How fossils form

1. Sediment burying the animal shortly after death.
2. Accumulation of sediment layers and mineral replacement.
3. Movement of tectonic plates.
4. Erosion exposing remains.

Methods of dating fossils

• Relative dating: determining age based on relationships to other fossils or events.
• Radiometric dating: determining age based on radioactive decay.

WEEK 5: TOPIC: The Chemistry of Life

SUB-TOPIC: Organic molecules, Inorganic Compounds & Minerals

Molecules for Life

Organic molecules contain C, H, and O (some N and P). Cells are made up of proteins, carbohydrates, lipids, nucleic acids and vitamins.

• Organic: Contains C, H and O.
• Inorganic: Does not usually contain C.
• Micro-nutrient: Element required in small quantities.
• Macro-nutrient: Element required in large quantities.

Inorganic compounds include water and mineral salts; organic compounds include carbohydrates, lipids, proteins, enzymes, vitamins, and nucleic acids.

Water

2 hydrogen atoms joined to 1 oxygen atom H_2O. 70-95% of cells are made up of water, a universal solvent.

Mineral salts

Elements required in large (macro) or small (micro) quantities. Plants obtain minerals from soil and fertilizers, while animals obtain minerals from food.

WEEK 6: TOPIC: The Chemistry of Life

SUB-TOPIC: Organic compounds (Monosaccharides & Lipids)

Carbohydrates

Carbohydrates are molecules found in our food that provides our brains and muscles with energy and are composed of carbon, hydrogen and oxygen atoms. Divided into simple (Monosacharides) and complex carbohydrates:

• Test for glucose: Add Benedicts solution to unknown solution. On heating the colour of solution will change from blue to orange/ brick red indicates the presence of glucose.
• Test for starch: Iodine turns from brown to blue-black.

Lipids

Lipids are fats found in all cell membranes in our bodies, are a source of energy, insulate nerve cells and don’t dissolve in water.

• Test for lipids: Fats and oils leave behind a grease spot stain on filter paper.

High cholesterol is a significant risk factor for coronary heart disease and a cause of heart attacks. Reducing the intake of cholesterol, saturated fat and trans fats help to manage cholesterol levels.

WEEK 7: TOPIC: The Chemistry of Life

SUB-TOPIC: Organic compounds (Proteins, Enzymes, Nucleic acids & Vitamins)

Proteins

Proteins are large organic molecules made of C, H, O, and N. made up of amino acids used by the body to build and repair muscles and bones and to make hormones and enzymes. Protein is a macronutrient found in all types of animal and plant foods. You need protein to build tissues, preserve lean muscle mass and to repair and maintain skin cells.

• Temperature and pH are factors that affect the structure of proteins. cause permanent changes to the bonds that hold the structure of a protein in shape and denatures it.
• Biuret reagent, a blue solution, is used to test for protein.

Enzymes

Enzymes are protein molecules that control metabolic reactions increase or slow down the rate of the reaction. They regulate almost every reaction in the human body. that are specific in their action; each enzyme regulates one particular reaction.

Nucleic acids

Found in a cell’s nucleus and are responsible for storing and transferring genetic information. There are two types of nucleic acids found in cells: DNA and RNA

Vitamins

Organic compounds known as micronutrients that are required in small quantities by animals to maintain health.
Some vitamins are water-soluble while some are fat-soluble

WEEK 8: TOPIC: Cells: The basic unit of life

SUB-TOPIC: Cell wall, cell membrane, nucleus & cytoplasm

Cell Wall

The cell wall is a rigid outer layer of plant cells made of cellulose. it Protects the inner parts of the plant cell, Gives plant cells a uniform and regular shape and Provide support for the plant body.

Cell membrane

The cell membrane surrounds the cytoplasm and is made up of lipid and protein molecules,. It is semi-permeable and controls the movement of substances into and out of the cells The fluid mosaic model describes the arrangement of lipid and protein molecules in cell membranes and it's important for diffusion and osmosis. The fluid mosaic model is a commonly accepted model that describes the arrangement of lipid and protein molecules in cell membranes.

• Diffusion movement of particles from an area of high concentration to an area of low concentration down a concentration gradient that occurs in living and non-living systems and is an example of passive transport – no energy is needed.
• Osmosis is the movement of water molecules across a selectively permeable membrane from an area of high water potential to a low water potential.
• Active transport involves the movement of substances through a semi-permeable membrane against a concentration gradient.

Nucleus

The nucleus is the largest organelle in the cell and contains all the cell’s genetic information in the form of DNA. presence of a nucleus is the primary factor that distinguishes eukaryotes from prokaryotes.
It has four main parts:

1. the double nuclear membrane: allows passage of substances in and out of the nucleus,
2. the nucleoplasm – jelly-like fluid
3. the nucleolus – dark body which contains nucleotide bases and produces ribosomes.
4. the chromatin network; contains the DNA which forms the chromosomes containing the genetic code of a person / organism.

Cytoplasm

Consists of up to 90% water. it Contais nutrients and waste products and its main function is It nourishes the cell by supplying it with salts and sugars and provides a medium for metabolic reactions to occur.

WEEK 9: TOPIC: Cells: The basic unit of life

SUB-TOPIC: Mitochondria, Ribosome, Endoplasmic reticulum & Golgi-body

Mitochondrion

A double membrane surrounds each mitochondrion’s fluid-filled matrix. contains finger-like projections called cristae, which contain their own DNA and produce energy in the form of ATP through the process of cellular respiration

Ribosomes

Small grain-like structures that is present in all forms of plant and animal cells and bacteria consisting of a smaller and larger subunit, Made up of protein and ribosomal RNA (rRNA) The primary job of ribosomes is protein synthesis linking amino acids together.

Endoplasmic reticulum

A system of tubules (Rough and smooth) continuous with the cell and nuclear membrane. They Transport ribosomes throughout the cell and Transports ribosomes throughout the cell using rough endoplasmic reticulum (RER), and Synthesizes lipids and steroids, e.g. cholesterol, on the smooth endoplasmic reticulum (SER).

Golgi apparatus(bodies)

A stack of flattened sacs and many spherical vesicles with Found in both animal and plant cells and The Golgi bodies are mostly found in gland cells that secrete substances e.g. goblet cells of the alimentary canal. Makes and processes secretions