B1- key concepts Flashcards
List the components of both plant and animal cells
- ribosomes
-mitochondria
-nucleus
-cell membrane
-cytoplasm
What is the function of the nucleus?
controlls celular activities and stores genetic information arranged in chromosones
What is the structure of cytoplasm
fluid component of the cell that contains oragnelles, enzymes and dissolved ions and nutrients
What is the function of cytoplasm
site of cellular reactions anf the i.e first stage of respiration
What is the function of mitochondria
Site of later stages or aerobic respiration win which ATP is produced
What is the function of the ribosomes
Joins amino acids in a specific order during translation
What is a cell wall made of ?
cellulose
What does the permanent vacuole contain?
A solution of salts, sugars and organic acids
What is the function of the permanent vacuole?
supports the cell, maintiang its turgidity
What organelles are found in a prokaryotic cell?
- chromosonal DNA
- Plasmid DNA
- Cell wall
- Cell membrane
- Ribosomes
- Flagella
How is genetic information stored in a prokaryotic cell ?
found free within the cytoplasm as:
-chromosonal DNA
-Plasmid DNA
What are plasmids?
- small circular loops of DNA found free in the cytoplam and seperate from the main DNA
- carry genes that provide genetic advantages
What is a prokrayotic cell wall composed of?
peptidoglycan
What is flagellum?
- Long, rotating ‘whip-like’ protusion
- Enables bacteria to move
What is a haploid cell ?
A cell that contains a single copy of each
chromosome (half the number of chromosomes)
- e.g. 23 chromosomes in humans
What is a diploid cell
A cell that contains two copies of each
chromosome (full set of chromosomes)
e.g. 46 chromosomes in humans
What is a diploid cell
A cell that contains two copies of each
chromosome (full set of chromosomes)
e.g. 46 chromosomes in humans
what are gametes
They are reproductive cells (haploid)
Describe how egg cells are adapted to their function
● Haploid nucleus contains genetic material
● Mitochondria in cytoplasm produce energy for the developing
embryo
● Cytoplasm contains nutrients for the developing embryo
● Cell membrane hardens after fertilisation, preventing the entry
of other sperm and ensuring the zygote is diploid
Describe how sperm cells are adapted to their
function
● Haploid nucleus contains genetic information
● Tail enables movement
● Mitochondria provide energy for tail movement
● Acrosome contains enzymes that digest the egg cell
membrane
Where are ciliated epithelial cells found?
Found lining the surface of structures such as the respiratory tract and uterus
Describe the function of ciliated epithelial cells lining
the airways
Move in synchronised waves to beat mucus (containing dirt and pathogens) up to the back of the throat where it can be
swallowed.
What is resolution?
The smallest distance between two
objects that can be distinguished
How does a light microscope work?
Passes a beam of light through a specimen which travels through the eyepiece lens, allowing the specimen to be observed.
What are the advantages of light microscopes?
- cheap
- easy to use
- portable
- used for live and dead specimens
How does an electron microscope work?
It uses a beam of electrons which are focused using magnets. The electrons hit a fluorescent screen which emits visible light, producing an image.
Name the two types of electron microscope
- Transmitting electron microscope (TEM)
- SCanning electron microscope (SEM)
Why do electron microscopes have a greater magnification and resolution?
They use a beam of electrons which has a shorter wavelength than photons of light
What are the disadvantages of electron microscopes?
- trainign required for use
- only dead specimins
- expensive
-l arge
How do you convert from m to μm?
x 1,000,000 (10^6)
How do you convert from m to nm?
x 1,000,000,000 (10^9)
How do you convert from m to pm?
x 1,000,000,000,000 (10^12)
What molecules enter and leave cells via simple diffusion through the cell membrane?
small molecules : oxygen, water, glucose, amino acids
What factors affect the rate of diffusion?
- tempurature
- surface area
- concentration gradient
Define osmosis
movement of water molecules from an area of high water concentration to an area of low water concentration through a
partially permeable membrane
What is active transport?
The movement of molecules across a cell membrane from an area of low concentration
to an area of high concentration, against the concentration gradient, using energy
What is diffusion ?
The movement of molecules from and area of high concentraion to low concentration down a concentration gradient
What is an advantage of enzymes in the body?
They enable cellular reactions to take place at lower temperatures
How can the rate of an enzyme-controlled reaction be calculated when given a value for time?
rate = 1/time
what are the units for rate?
S^-1
Why must large organic molecules be broken down into smaller, simpler molecules in the body?
● Large molecules are too big to be absorbed across
the surface of the gut wall
● ∴ large molecules are broken down into smaller
molecules for absorption into the bloodstream
Give an example of the breakdown of large molecules into smaller molecules in plants
Starch is broken down by enzymes into simpler sugars which are respired to release energy.
What are the monomers of carbohydrates?
simple suars
Which group of enzymes catalyses the breakdown of carbohydrates?
Carbohydrases
Which type of carbohydrase catalyses the breakdown of starch?
Amylase
What are the monomoers of protein?
Amino acids
WHich type of enzyme catalyst brewaks down protein?
Protease
What is the function of lipases?
Enzymes which catalyse the breakdown of lipids into fatty acids and glycerol
Why are small molecules synthesised into larger
organic molecules in the body?
Large molecules are used for storage (e.g. glycogen) or are used to build structures (e.g. organelles).
Which enzyme catalyses the formation of glycogen
from glucose?
Glycogen synthase
What is calorimetry?
A method of measuring the heat transfer during a chemical reaction (the amount of energy contained ina food)
Describe the method used to measure the amount of
energy in a sample of food
- Add a set volume of water to a boiling tube, record initial temperature
- Record the mass of a small sample of food (e.g. bean)
- Stick the sample onto a mounted needle
- Using a bunsen burner light the food sample
- Hold the sample under the boiling tube until it burns up
- Record the maximum temperature reached by the water
- Record the final mass of the food sample
