Cell Requirements & Microscopes Flashcards
Why are cells the basic unit of life?
- easily recognised package
- surrounded by a membrane
- highly organised structure
- site of many chemical processes and reactions
- able to sense and respond to changes in their environment
- have the potential to reproduce itself and it even stores its own set of instructions for carrying out these activities
- can survive on its own or has the potential to do so.
What is the difference between prokaryotic and eukaryotic cells?
Prokaryotes:
- No nucleus
- Non membranous organelles
- All reactions take place in the cytoplasm
Eukaryotes:
- Membrane-bound
- Compartmentalised organelles
- Larger
- Distinct nucleus
How have membrane bound organelles contributed to complexity and biochemical efficiency in eukaryotes?
- Membrane bound organelles can have a niche for reactions
What is the endosymbiotic theory?
A theory about how the mitochondria and chloroplast used to be smaller organisms that were engulfed by larger organisms and not fully digested so they could maintain their function within the larger cell
Ten organelles/structures in cells
– Nucleus: control centre
– Ribosome: protein synthesis
– Golgi bodies: packaging
– Mitochondria: energy
– Centrioles: cell division
– Vacuoles: storage
What are the features of carbohydrates?
Features of carbohydrate:
– Made of sugar units called saccharides
– Found in starch
– CHO
What are the features of protein?
– CHO
– Polypeptides
– Peptides
– Examples: Keratin, collagen
– Used for structure and function in the body
What are the features of fats (lipids)?
– CHO
– Common fats: oil, terpene, butter
– Component of cell membrane
What are special organelles in a cell that aid in the packaging and removal of waste?
- Liposomes
- Golgi apparatus (packaging and produces bubbles)
- Endoplasmic reticulum (supports transport)
- Vesicles (pinch off from apparatus)
What is simple diffusion?
Things move in a cell from a region of high concentration to a low region of concentration
What is osmosis?
The movement of water molecules from high to low concentration through semi-permeable membranes.
What is facilitated diffusion?
Where the particles are too large so they need to go through certain areas or be assisted by carrier proteins
Active transport?
Against a concentration gradient so it needs energy (ATP) to attach to the carrier proteins to push the particle from low to high concentration.
What is exocytosis?
Expulsion of something from the cytoplasm through a bubble that fuses
What is endocytosis
Taking things in; it can do this by either growing around the food particle by absorbing it or by the tiny particles on the membrane.
Pinocytosis: tiny particles that hit against the membrane
Phagocytosis: large food particles that the membrane moves around to engulf
4 factors that affect transport across a membrane
- Concentration
- Surface area to volume ratio
- Physical properties (size)
- Chemical properties (charge or no charge)
Concept of metabolism and the role of enzymes
Metabolism: sum of all chemical reactions in the body
(catabolic or anabolic)
(endogonic or exogonic)
Enzymes speed up reactions
3 features of enzymes
- specialised active site
- reversible enzymes (catabolic reaction can become anabolic reaction, vise versa)
- speeds up reaction
Five factors that affect enzymes
- Temperature (enzymes can function until a certain temperature when they denature
- pH (same as temp.)
- Concentration (enzyme conc. and substrate conc. increase until they are the same and depend on each other)
- Inhibition (when inhibitors temporarily stop the enzymes from working) Competitive inhibition: fights for the active site and changes shape
- Assistance (coenzymes that help reaction and cofactors)
Photosynthesis stages
3 factors that affect photosynthesis
- Light (increase in light increases food production up to a certain point after which it stabilises)
- CO2 (same as light)
- Temperature (increases up to a point where the enzymes denature and the plant dies)
Relationship of photosynthesis and cellular respiration
The products from one become the reactants for the other
What is metabolism?
The sum of all chemical reactions in the body.
What are the two categories of metabolism?
Catabolism and anabolism
