Introduction To Biology

INTRODUCTIon to BIOLOGY… Explanation Meaning of Biology

-

Importance of Biology

Application

Fields of Biology

from Greek words: a) bios – life b) logos – study hence, biology is the study of living things

a) understand ourselves and our surrounding environment. b) understand the interaction between living things and the environment. c) Appreciate and be thankful for the diverse variety of living things. a) in the field of medicine and public health - to create new medicine to cure diseases - to invent modern medical equipment and procedures to treat patients - to invent new vaccines to prevent or treat diseases - to improve one’s health and well-being b) in agriculture - to produce high quality agricultural products - to clone plants and animals of good strains - to control and overcome the problem of pests c) in industry - to produce nutritious foods - in food processing and preservations d) in research - in genetic engineering - in conservation and preservation of endangered species a) genetics – study of heredity b) virology – study of viruses c) entomology – study of insects d) anatomy – study of the structure of organisms e) ecology – study of the environment and its relationship with organisms f) botany – study of plants g) zoology – study of animals h) embryology – study of embryonic development i) taxonomy – study of classifications of plants and animals j) histology – study of tissues k) bacteriology – study of bacteria l) physiology – study of biochemical processes in the body

Biology, Form 4, amirah_aziz

Scientific skills

Scientific Method

a) science process skills - promote thinking in a critical, creative, analytical and systemic manner - eg: observing, classifying b) manipulative skills - are psychomotor skills acquired through conducting experiments in scientific investigation a) b) c) d) e) f) g) h) i) j)

identifying the problems forming a hypothesis planning an experiment controlling variables conducting the experiment collecting data analysing data interpreting data drawing conclusions writing a report

Biology, Form 4, Cell structure and cell organisation… amirah_aziz

Explanation Function of cell Protoplasm Differences between animal cell and plant cell

-

carry out life processes such as respiration, excretion, growth and division

Cytoplasm and nucleus Animal cell No fixed shape Absent Absent

Similarities between animal cell and plant cell

Organelles

Cellular components

Differences … SHAPE

Plant cell

CELL WALL

Present

CHLOROPLA STS

Present which contain chloroplast Has large vacuoles

Usually VACUOLE exists as numerous small vacuoles in lower animal cells Glycogen GRANULES granules a) plasma membrane b) cytoplasm c) nucleus d) mitochondria e) Golgi apparatus f) Endoplasmic reticulum

Fixed shape

Starch granules

Specialised structures which are each surrounded by its own membrane and perform specific functions EXAMPLE: a) nucleus b) rough endoplasmic reticulum and smooth endoplasmic reticulum c) mitochondria d) Golgi apparatus e) Lysosomes f) Ribosomes g) Centrioles h) Vacuole

Structures

Biology, Form 4, amirah_aziz Biology, Form 4, Functions amirah_aziz

Plasma membrane Cell wall

- thin , semi- permeable membrane -

Cytoplasm

-

Nucleus

-

Ribosomes

-

Mitochondria

-

Golgi apparatus

-

thick layer outside the plasma membrane made up of cellulose and fully permeable jelly-like substance that contains water and mineral salts contains organelles spherical with a double membrane contain nucleolus, chromosomes, nucleoplasm and nuclear membrane small particles consisting of RNA (ribonucleic acid) exists freely in the cytoplasm or on the surface of the endoplasmic reticulum rod-shaped with a double membrane outer membrane is smooth and regular while the inner membrane is folded to form cristae vacuolar region surrounded by a complex meshwork of vesicles budding off at its end

-control the movement of substances in and out of the cell - maintains the shape of plant cells - provide support for plant body -

acts as a medium for metabolic reactions supplies the substances required by organelles controls and regulates all the activities of the cells contains hereditary factors (genes) responsible for the traits of the animal and plant

- synthesis of protein

-

-

-

-

known as the ‘power house’ of the cell releases energy as it is the site for aerobic respiration

receives protein and lipids from endoplasmic reticulum and modify them to form specific secretions such as enzymes and hormones pack the secretion formed into secretory vesicles and transport them to the plasma membrane to be secreted controls the secretory activity of the cells formation of lysosomes Biology, Form 4, amirah_aziz

Lysosomes

-

membrane-bound vesicles found in animal cells

Chloroplasts

-

disc-shaped organelles with a double membrane consist of an orderly arrangement of grana with the stroma. Each granum contains chlorophyll consists of two cylindrical body structures arranged at right angles to one another found only in animal cells cavities filled with cell sap surrounded by a semipermeable membrane called the tonoplast a system of membraneenclosed tubules closely packed together and continuous with the nuclear membrane rough endoplasmic reticulum has ribosomes while the smooth endoplasmic reticulum does not have ribosomes

-

Centrioles

-

Vacuoles

Endoplasmic reticulum

-

-

-

-

contains enzymes which control breakdown of protein and lipids - contain enzymes that digest aged or defective cell components or materials taken in by the cell from its environment such as food particles or bacteria - carry out photosynthesis

-

formation of spindle during cell division

-

contains water, sugar and dissolved minerals maintains turgidity of cells in plants

-

-

-

transport system for protein and lipids within the cell rough endoplasmic reticulum transport the proteins synthesised by the ribosomes to other parts of the cell smooth endoplasmic reticulum stimulates the synthesis of lipids and cholesterol and transport them within the cell

Relationship between the density of organelles

-

Unicellular organism

Sperm cells – have many mitochondria to provide energy for the sperm to swim towards an ovum and fertilise it. Flight muscle cells – enable the animals to move their wings during flight. These muscle cells have a high density of mitochondria. Cells in meristems - actively involved in cell division to produce new cells for growth. Cell division requires energy. Single-cell organisms such as Amoeba sp. and Paramecium sp. Biology, Form 4, amirah_aziz