cells

• The cell membrane is a selectively permeable barrier that surrounds the cell and regulates the movement of substances in and out of the cell.
• Mechanical breakdown occurs when food is chewed to break it down into smaller pieces that can be swallowed easily.
• The digestive system is made up of the mouth, oesophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (caecum, colon, rectum) and anus.
• Golgi apparatus is involved in modifying, sorting, and packaging proteins for transport.
• Mitochondria are responsible for producing energy in the form of ATP through cellular respiration.
• The nucleus contains genetic material (DNA) and controls cellular activities such as growth, metabolism, and reproduction.
• Ribosomes are structures involved in protein synthesis.
• Mitochondria are organelles responsible for producing energy through cellular respiration.
• Chemical digestion involves enzymes breaking down large molecules into smaller ones, such as starch being broken down into glucose by amylase.
• Absorption takes place through the walls of the small intestine, where nutrients are absorbed into the bloodstream or lymphatic vessels.
• Lysosomes contain enzymes that break down waste products inside the cell.
• Mitochondria produce energy through aerobic respiration.
• Ribosomes synthesize proteins using information from DNA and RNA.
• Lysosomes contain enzymes that break down waste materials within cells.
• Ribosomes synthesize proteins using information from DNA.
• Endoplasmic reticulum is involved in the production and modification of proteins.
• prokaryotic cells dont have membrane enclosed organelles
• eukaryotes have membrane bound organelles
• prokaryote examples are bacteria and archaea
• eukaryote examples are plant, animal and protists
• both prokaryotes and eukaryotes have DNA, ribosomes and a cell membrane
• the cell membrane consists of a double layer phospholipids that controls what comes in and out of the cell
• DNA can be copied into a single strand called mRNA that can leave the nucleus through a nuclear pore
• intracellular proteins are made and used within the cell
• extracellular proteins are made by the cell and released out of it e.g. hormones and antibodies
• endoplasmic reticulum is a network of tubules called cisternae
• mitochondria produces ATP by aerobic respiration
• lysosomes break down waste material as they contain enzymes
• components of the cell membrane are phospholipids, choleseterol and two types of proteins, intrinsic and extrinsic
• phospholipids have a polar- hydrophilic head that faces outside and two fatty tails that are non-polar- hydrophobic and they face inside
• cholesterol helps to maintain fluidity of the membrane
• small lipids soluble molecules, o2 and co2 can pass through the membrane by simple diffusion
• passive/simple transport doesnt require ATP and its from a high to low concentration
• active transport is the movement of molecules from a low to high concentration so requires ATP
• ion pumps require ATP and bulk transport such as endocytosis and exocytosis require ATP
• endocytosis involves the cell engulfing material into vesicles which then fuse with lysosomes where digestion occurs
• endocytosis is when the plasma membrane fold inwards, engulfing the substances so they enter the cell
• examples of endcytosis is phagocytosis which is when pathogens are taken in and pinocytosis which is when fluid is taken into the cell
• exocytosis is when substances move towards the cell membrane and fuses with it to leave the cell
• factors that affect the rate of diffusion are the size of the particle, temperature, concentration differences, diffusion distance, surface area and permeability