[BIO] Chapter 1 - Cell Structure and Organisation

© Hee Xin Wei (Copyrighted) Topic 1: Cell Structure and Organisation

Chapter Analysis FOCUS EXAM WEIGHTAGE © Hee Xin Wei •usually tested in MCQ •straightforward chapter •animal cell, plant cell, specialised cells •light weightage

organelle functions specialised cells Key Concept

Animal Cell © Hee Xin Wei

Plant Cell © Hee Xin Wei

Organelle Functions Present in both animal and plant cells © Hee Xin Wei Cell Membrane Partially permeable, controls substances entering or leaving the cells. Nuclues Controls cellular activities such as growth, repair, and cell division. •Nucleolus: plays a part in the making of proteins in the cell. •Chromatin: long strands of DNA. Cytoplasm •Made up of 90% water and contains dissolved protein, sugars, enzymes. •Embedded with organelles (eg mitochondria, RER, SER, Golgi body). •Sites of most cellular activities. Vacuole •Animal: store water and food substances •Plant: store water, with food substances and mineral salts. also takes in waste products and water. Mitochondria Carry out aerobic respiration to release energy, energy is used to carry out cellular activities

Organelle Functions Present in both animal and plant cells © Hee Xin Wei Ribosomes •Can either be attached to RER or free floating. •Site of protein synthesis. Rough endoplasmic reticulum Ribosomes are attached to the membrane (thus rough) RER is involved in protein synthesis Smooth endoplasmic reticulum •Synthesises fats and steroids such as sex hormones. •also contains enzymes that detoxify drugs and poisons. Golgi Body It stores, sorts and modifies substances made by the ER, and packages them in vesicles to be secreted out of the cell. RER Ribosome golgi bodySER involved in the movement of substances (protein) out of cells

Organelle Functions Present ONLY in either animal or plant cells © Hee Xin Wei Organelle Present only in Functions Cellulose cell wallPlant Cell Fully permeable, protects the cell from injury and gives the cell its shape. Chloroplast Plant Cell Contains chlorophyll. They are the sites of photosynthesis, which is the process by which plants make food. Centrioles Animal Cell Help with cell division in animal cells

Compare the structure of typical animal and plant cells Animal Cells Plants Cells Cellulose cell wall Absent Present Vacuole Small and numerous A large and central vacuole Chroloplast Absent Present Centriole Present Absent generally © Hee Xin Wei

Specialised Cells RED BLOOD CELLS •Function: deliver oxygen to the body tissues via the blood. •Cell structure adaptations: •RBC contain haemoglobin which binds with oxygen and transports it from the lungs to all parts of the body •RBCs have no nucleus, thus have more capacity for haemoglobin •RBCs have a flattened biconcave shape. This increases the surface area to volume ratio for faster diffusion of oxygen. It also allows the cell to be more flexible when squeezing through blood capillaries. © Hee Xin