B2 Flashcards
Definition of chloroplasts
Contain chlorophyll which is needed for photosynthesis
Definition of mitochondria
Convert glucose and oxygen into energy in a process called respiration
Definition of nucleus
Controls the activities of the cell. Contains chromosomes (which have genes in them)
Definition of vacuole
Filled with water and dissolved chemicals (cell sap). Stores minerals
Definition of cytoplasm
Part of the cell where all the chemical reactions take place
Definition of cell wall
Strengthens the cell and maintains the shape of the plant. Made of cellulose
Definition of cell membrane
The skin surrounding the cell. Controls the movement of substances into and out of the cell
Definition of diffusion
Spreading of particles from an area of higher concentration to an area of low concentration. Passive(no additional energy needed)
Factors affecting diffusion
- concentration gradient-higher=faster diffusion
- surface area-larger SA: volume ratio=faster diffusion
- diffusion pathway-smaller diffusion pathway=faster diffusion
- temperature -higher=more kinetic energy=faster diffusion
- size of particle-smaller=faster diffusion
Definition of a cell
The smallest structured and functional unit of an organism
Definition of a tissue
A group of a specialised cells al carrying out the same function
Definition of organ
A group of different tissues working together to carry out a specific function
What does the palisade layer contain
Contains the most chloroplasts as it receives the most light
What does the lower epidermis do and contain
Has holes called stomata (controlled by guard cells). These allow has exchange
Veins…
Carry water and nutrients from roots to the leaf cells and carry glucose away
Photosynthesis equation
Carbon dioxide + water —> glucose + oxygen
6CO2+6H2O—> C6H12O6+6O2
Limiting factors of photosynthesis
Light intensity
Carbon dioxide concentration
Temperature
Aerobic Respiration reaction
Needs CO2 to happen in the cells mitochondria when glucose reacts with O2 and provides energy
Aerobic Respiration reaction equation
Glucose +oxygen —> carbon dioxide + water + (energy)
Anaerobic Respiration reaction
Glucose—> lactic acid + (energy)
Why do living organisms require energy?
Building large molecules from smaller ones
Muscle contractions
Controlling body temperature
Definition of ribosomes
Synthesise proteins from amino acids
What is oxygen debt
If you use anaerobic respiration to provide energy then the muscles cells break down glucose to lactic acid.
Lowers pH of muscle tissue
Breathing needs to increase so you can use some of the extra oxygen to oxidise the lactic acid to carbon dioxide and water. This is repaying oxygen debt
What is muscle fatigue
If muscles are subjected to long periods of vigorous activity they become fatigued
Muscle fatigue happens if insufficient oxygen is reaching the muscles they use anaerobic respiration to obtain energy
Definition of biodiversity
Number of living different organisms in an area
Definition of niche
The part of a habitat that an animal is adapted to
Definition of sampling
Taking measurements at several points to allow us to make assumptions of the area as a whole
Definition of distribution
Where an organism can be found
Random sampling is…
Used to eliminate bias in collecting data
Systematic sampling…
Is when samples are taken at regular intervals within a set sampling area
What is an enzyme?
A biological catalyst which speeds up the rate of reaction.
Is a protein
Each enzyme is specific to a substrate
Optimum temperatures
Different enzymes have various optimum temperatures
What is the lock and key theory?
In the same way that a key fits into a lock, so a substrate is thought to fit into an enzymes active site. The enzyme is the lock and the reactant is the key.
Enzyme + reactant enzyme reactant complex enzyme + products
What is denaturing
When the active site irreversibly changes shape
What does the mouth do in the digestive system?
Mechanical
Uses amylase (to begin chemical digestion) to lubricate food to make it easy to swallow
What does the oesophagus do in the digestive system?
Tube takes food to the stomach. Muscles push the food along the gut in a wave called PERISTALSIS
What does the stomach do in the digestive system?
Secretes gastric juice:
Contains hydrochloride acid which -kills germs
-makes the right pH for enzymes to work
Pepsin starts protein digestion and sphincters shut off stomach whilst being churned
What does the small intestine do in the digestive system?
Receives bile from liver - mechanical (fat digestion)
Lipase, fats into glycerol (lipids)
Amylase, starch (+carbohydrase) info glucose
Propase, proteins (+protease) into amino acids
What does the large intestine do in the digestive system?
Absorbs 90%of the water
Faeces made up of mainly cellulose
Amylase
Breaks down starch into sugar molecules
Does this is in the mouth and small intestine
Made in salivary glands and pan crease and small intestine
Protease
Breaks down protein into amino acids
Does this in the stomach and small intestine
Made in the stomach pancreas and small intestine
Lipase
Breaks down lipids (fat molecules) into fatty acid glycerol
Does this in the small intestine
Made in pancreas and small intestine
What are enzymes made from?
Proteins
What do enzymes do
Speed up rate of reaction
How do they work
Lock and key mechanism
What are three industrial uses of enzymes
Biological detergent
Baby food
Fruit juice
What is bile, what does it do and how does it do it ?
Emulsifies fats so that it has a large surface area
Liquid substance made in liver stored in gall bladder released into small intestine
Neutralises stomach acid
Immobilising enzymes
Enzymes are expensive so to save money they can be mobilised
This means they can be filtered from the product and used again
Why are enzymes needed to produce slimming products
Changing glucose into fructose (which is sweeter) means that less is needed to be used
Where are proteins made?
Ribosomes in all body cells
What reaction does amylase catalyse?
Where does the reaction happen?
Starch ~~> glucose
Salivary glands, pancreas and small intestine
What two main factors can affect the rate at which an enzyme works
Temperature
pH levels
What reaction does protease catalyse?
And where does the reaction take place?
Proteins~~> amino acids
Stomach, pancreas, small intestine
Why doesn’t a biological detergent work well at 60 degrees ?
Passed the optimum and enzymes begin to denature
What is energy?
The ability to do work
Each form of energy can be transferred to another
Why do living organisms require energy?
Building large molecules from smaller ones
Muscle contraction
Controlling body temperature
Growth
DNA
Molecules are large and complex. They carry the genetic code that determines the characteristics of a living thing
Genes
Section of dna which codes for a specific protein by specifying the order in which amino acids must be joined together
Chromosomes
The cells nucleus contains chromosomes made from large dna molecules
Describe mitosis
100%- chromosomes in nucleus are copied. They line up ready for division
200%- cell division starts and chromosomes begin to separate
2x(100%)-two identical diploid daughter cells produced
Describe miosis
100% 46 chromosomes PARENT CELL chromosomes make identical copies of themselves
200% 46 chromosomes, similar chromosomes pair up
100% 23 chromosomes each, sections of DNA get swapped, pairs of chromosomes divide
50% 23 chromosomes each
Where does mitosis occur?
In all cells of the body
Where does meiosis occur?
Ovaries or testies
What are the number of the divisions in mitosis?
1
What are the number of the divisions in meiosis?
2
How many cells are created in mitosis?
What are the number of chromosomes at the end?
2 cells
46 (23 pairs)
How many cells are created in meiosis?
And what are the number of chromosomes at the end?
4 cells
23
Mitosis produces…
Identical daughter cells
Meiosis produces…
Gametes
What is the function of mitosis?
Repair and growth
What is the function of meiosis?
Production of egg and sperm cells
What is cystic fibrosis
Disorder of the cell membranes
Sufferers produce too much mucus which clogs the lungs and digestive system
Caused but a recessive allele
Heathy NN
Carrier Nn
Sufferer nn
What is polydactyly?
Means having more digits
Caused by a genetic disease with a dominant allele
Sufferer PP, Pp
Heathy pp
No carriers
What’s the method of embryo screening
Dna is isolated from embryo
A gene probe that will bind onto the gene for a specific disorder is produced
The probe has a fluorescent chemical attached to it
The probe is added to the mixture containing the dna sample from the embryo
Uv light is used to detect the probe attached to the gene for the disorder
What is embryo screening uses
Ivf allows to check for genetic disorder
What’s the method for stem cells
Take a bone marrow sample or stem cell embryo and then use for research
What is the method for Dna fingerprinting
Collect a sample of Dna
Use an enzyme to cut dna into sections
Separate sample by gel electrolysis
Compare bands of Dna against Unknown/known samples
What is speciation
Is the separate evolution of two populations of the same species to form two separate species
Describe speciation
Species || Population split || Isolation || Different environmental conditions || Independent evolution || If they were to meet again they'd no longer be able to reproduce
What is an allele
Different form of the same gene
Dominant
Recessive
