M1 - Cells are the basis of life Flashcards
What is a prokaryote?
-Smaller and simple structure
-Unicellular
-no membrane bound organelles
-asexual reproduction
-e.g bacteria
What is a eukaryote?
-Larger and complex structure
-unicellular and multicellular
-membrane bound organelles
-sexual reproduction
-e.g animalia and plantae
What is an organelle?
A membrane-bound structure that performs a specialised function within a eukaryotic cell
What is the structure and function of the mitochondria?
-Smooth outer layer and rippled inner layer
-The powerhouse of the cell and site of cellular respiration where energy is produced.
What is the structure and function of the nucleus?
-Large organelle with a double membrane
-Contains most of the cell’s DNA and controls chief functions such as growth and metabolism
What is the structure and function of the endoplasmic reticulum?
-A network of sacs which allows materials to be transported
Describe the role of the smooth ER
-Synthesises lipids and hormones
Describe the role of the rough ER
-Has ribosomes and is the site of protein synthesis
What is the structure and function of the golgi apparatus?
-Stack of flattened sacs
-Modify and package proteins for exportation
What is the structure and function of the chloroplast?
-Double membrane containing chlorophyll and small structures called thylakoids
-Site of photosynthesis
What is the structure and function of the lysosome?
Sphere-shaped sacs filled with enzymes which break down macromolecules into micromolecules
What is the structure and function of the vacuole?
A large sac that stores nutrient, water and waste
What are the steps to calculating DFOV?
- Count lines
- Divide by 10
- Times by 1000
- Count cells across
- Divide DFOV by cells across
- Scale
- Draw
What does a scaled diagram require?
Title (name of cell), labels, magnification, scale bar, l x w
What parts make up the external cell membrane?
Carbohydrate chain, glyocolipid, glycoprotein
What parts make up the lower half of the fluid mosaic model?
Internal cell membrane, phospholipid bilayer, protein molecule, cholestrol
What parts make up a phospholipid?
Hydrophilic head and hydrophobic tail
What is the purpose of models?
Representing observations and conceptual ideas and making prediction
What is passive transport?
The movement of substances across a cell membrane without the use of energy
What is diffusion?
The net movement of any molecules from a region of high concentration to a region of low concentration until an equilibrium is reached.
What factors affect rate of diffusion?
-Temperature
-Concentration difference
-Surface area
What is simple diffusion?
The diffusion of substances across a membrane without the assistance from other substances
What is facilitated diffusion and why is it used?
The movement of molecules across a membrane via the aid of a membrane protein such as a channel or carrier protein.
It is used by molecules unable to freely cross phospholipid bilayer including large, polar molecules and ions.
Compare and contrast a channel protein and a carrier protein
Both proteins are utilised for facilitated, passive diffusion of molecules across a membrane. Channel proteins transport down the concentration gradient while carrier proteins transport both down and against the concentration gradient
What is osmosis?
The net diffusion of water molecules across a semipermeable membrane through aquaporins from high concentration to low concentration until an equilibrium is reached
Identify and explain the three concentrations of solutions
Hypotonic: concentration of solute is greater inside than outside so water moves into cell and expands. (lyse)
Isotonic: concentration of solute is equal inside and outside so no net movement occurs
Hypertonic: concentration of solute is greater outside than inside so water moves out of cell and shrinks (crenation)
What is the surface area to volume ratio and what is its significance?
The ration compares the total external surface area to the volume which determines how efficient a substance moves in and out of a cell.
Why do cells limit their size?
Smaller cells make transportation faster and more efficient. If metabolic rate exceeds the rate of exchange the cell dies
How is SA:V ratio increased by cells?
-Dividing to stay small
-Cell compartmentalization: eukaryotic cell organelles working in separate areas to reduce amount of exchange
-Membrane extensions: extend surface area e.g. microvilli and root hairs
What types of energy are required by cells and why?
Energy is needed for processes in cells including active transport and protein synthesis.
Light energy -> photosynthesis
Chemical energy -> absorption of glucose
What are autotrophs?
Organisms which produce their own organic compounds from inorganic compounds in soil and atmosphere.
e.g. Plants that photosynthesize
What are heterotrophs?
Organisms which obtain organic compunds by consuming other organisms.
e.g. all animals and fungi
What are organic and inorganic compunds used for?
-building blocks for cells and tissues
-stored source of energy
What differentiates an organic compound to an inorganic compound?
Organic compounds have carbon attached to the hydrogen molecule while the carbon if present in inorganic compounds are not attached to the hydrogen
What do cells need carbohydrates for? What are some forms of it?
energy sources and structural components
-includes glucose and starch
What do cells need lipids for?
energy storage, chemical messaging and structural membrane components
What do cells need protein for?
Structural component, growth, enzymes
What do cells need nucleic acid for?
DNA: Stores genetic information and instructions for cell function
RNA: Creates ribosomes
What do cells need vitamins for?
Cell reproduction and growth
What do cells need water for?
Transport medium, solvent, photosynthesis
What do cells need carbon dioxide for?
Photosynthesis and source of carbon for organic molecules
What do cells need oxygen for?
Cellular respiration
What do cells need nitrogen for? organic or inorganic ?
Amino acids for protein synthesis, form nucleic acid
What do cells need minerals for?
Building enzymes and for structure and function
What is photosynthesis and what is the equation?
Photosynthesis is the process occurring in the chloroplast where plants use sunlight to turn carbon dioxide and water into oxygen and glucose
6H20 + 6CO2 -> C6H12O6 + 6O2
Explain the two stages of photosynthesis
Stage 1 is the light depended reaction where sunlight is captured and water produces hydrogen ions, oxygen and ATP
Stage 2 is the light independent reaction occurring in the stroma where the hydrogen ions, ATP and carbon dioxide produces glucose , water and ADP
What factors affect the rate of photosynthesis?
-Carbon dioxide levels
-Temperature (until optimum point)
-Light intensity
What is cellular respiration?
A chemical reaction in cells where glucose and oxygen produces useable energy, carbon dioxide and water
What is the first stage of cellular respiration?
Stage 1 is glycolysis where glucose molecules split into 2 pyruvate and 2 ATP
What is aerobic respiration?
Respiration occuring in the mitochondria with the presence of oxygen. Glucose is broken down to Produce 2 pyruvate and 2 ATP. The pyruvate produces carbon dioxide, water and 34 ATP. In total 36 ATP are produced
What is anaerobic respiration?
Energy produced in cytosol without the presence of oxygen.
-Alcohol fermentation: glucose -> 2 pyruvate and 2 ATP -> ethanol and CO2
-Lactic acid fermentation: glucose -> 2 pyruvate and 2ATP -> lactic acid. Glycolysis repeats and when exercise is over, aerobic respiration can occur using lactic acid.
Why is waste removal necessary?
For organisms to maintain balance and homeostasis
Identify and explain the two forms of waste removal
Passive: through osmosis of water and oxygen diffusion
Active: urea and toxins removed through endocytosis and exocytosis
How do Autotrophs remove waste?
Autotrophs produce almost no true waste as they have a low metabolic rate, fewer protein molecules and reuse gas. Some plants can past chemicals into the environemnt.
Explain how carbon, water and urea is removed from organisms
Carbon is produced by cellular respiration and removed by the respiratory system
Water is produced by cellular respiration and consumed, removed by the excretory system
urea is produced by digestion and removed through the excretory system
What are 2 waste removing organs and what are their roles?
The liver is used for preparing substances for excretion, detoxifying chemicals and destroys worn or red blood cells
The kidney is use to filtrate the blood from toxins and produce urine
