B P1 - Cell Biology (structure, division) Flashcards
What is the cytoplasm?
The cytoplasm is the site of chemical reactions in the cell, which contains enzymes to catalyse the reactions
What is the nucleus?
The nucleus contains genetic material and controls the activities of the cells and codes for proteins
What is the cell membrane?
The cell membrane is semi-permeable and controls the movement of substances in and out of the cell
What is the ribosome?
The ribosome is the site of protein synthesis, where mRNA is translated to an amino acid chain
What are the mitochondria?
The mitochondria are the site of respiration where energy is released for the cell to function
What is bacterial DNA?
Bacterial DNA controls the function of a bacterial cell and floats in the cytoplasm as it is not in the nucleus
What is the cell wall?
The cell wall supports and strengths the cell (it is not made of cellulose)
What is the plasmid?
The plasmid are small rings of DNA that contain additional genes
What is the permanent vacuole?
The permanent vacuole contains cell sap and keeps the cell turgid, and contains sugars and salts in solution
What is the chloroplast?
The chloroplasts are the sites of photosynthesis that contain chlorophyll and absorb light energy
What are the differences between eukaryotes and prokaryotes?
Eukaryotes are complex organisms such as plant and animal cells which contain a nucleus, whereas Prokaryotes are simple organisms such as bacterial cells which do not contain a nucleus
What is cell differentiation?
Cell differentiation is how a cell changes and becomes specialised
What are undifferentiated cells called?
Undifferentiated cells are called STEM cells
How do you calculate magnification?
Magnification is the size of the image divided by the real size of the object
What are the features of light microscopes?
Light microscopes use light rays for radiation, their max magnification is 1500, the resolution is 200nm, they are small and portable, and are cheap
What are the features of an electron microscope?
An electron microscope uses electron beams for radiation, their max magnification is 2,000,000, their resolution is 0.2nm, they a very large but not portable and are expensive
How are nerve cells specialised? (animal)
Nerve cells, which carry electrical impulses, have long connections to communicate with other nerve cells and also has an insulation sheath called myelin
How are sperm cells specialised? (animal)
Sperm cells, which fertilises eggs, have long tails, has acrosome which contains enzymes, and contain a large number of mitochondria
How are muscle cells specialised? (animal)
Muscle cells, which contract to allow for movement, contain a large number of mitochondria and are also very long
How are root hair cells specialised? (plant)
Root hair cells, which absorb water and minerals from the soil, have hair-like projections to increase their surface area
How are xylem cells specialised? (plant)
Xylem cells, which carry water and minerals, allow for transpiration, their cell walls are toughened by lignin and flow in one direction
How are phloem cells specialised? (plant)
Phloem cells, which carry glucose, allow for translocation, have endplates with holes and flow in both directions
What is translocation?
Translocation is the movement of sugars from photosynthesis around the plant
What is the equation of photosynthesis?
The equation of photosynthesis is carbon dioxide + water > glucose + oxygen
What is a chromosome?
A chromosome is a thread-like structure of coiled DNA found in the nucleus of eukaryotic cells
What is DNA?
DNA is a polymer made up of two strands forming a double helix
What is a gene?
A gene is a selection of DNA that codes for a specific protein or characteristic
Why are cells adapted for diffusion?
Cells are adapted for diffusion because the greater the difference in concentrations, the faster the rate that diffusion will be
What is diffusion? (energy is not required)
Diffusion is the movement of particles from an area of high concentration to an area of low concentration
What is osmosis? (energy is not required)
Osmosis is the movement of water from an area of high concentration to an area of low concentration across a semi-permeable membrane
What is active transport? (energy is required)
Active transport is the movement of particles from an area of low concentration to an area of high concentration
What factors affect the rate of diffusion?
The factors which affect the rate of diffusion are concentration, temperature and surface area
Name an example where diffusion is carried out
Diffusion is used during gas exchange of oxygen and carbon dioxide as well as urea in kidneys
Name an example where osmosis is carried out
Osmosis is carried out when plants absorb water from the soil by osmosis through their root hair cells
Name an example where active transport is carried out
Active transport is carried out during the movement of mineral ions into roots of plants and the movement of glucose into the small intestines
How are small intestines adapted for diffusion?
Small intestines are adapted for diffusion by increasing their surface area and having a good blood supply to maintain a concentration gradient
How are the lung adapted for diffusion?
The lungs have alveoli, which has increased surface area and good blood supply
How are gills in fish adapted for diffusion?
Gills in fish increases their surface area and had a good blood supply
How are roots adapted for diffusion?
Roots are adapted for diffusion by increasing their surface area
How are leaves adapted for diffusion?
Leaves are adapted for diffusion by having a large surface area and having thin leaves for a shorter diffusion path
What are the characteristics of human embryonic stem cells?
Human embryonic stem cells can be cloned and made to differentiate into most cell types.
What is therapeutic cloning of human embryonic stem cells?
Therapeutic cloning of human embryonic stem cells involves using the same genes so the body does not reject the tissue, but that increases the risk of infection
What are the characteristics of adult bone marrow stem cells?
Adult bone marrow stem cells can form many types of human cells such as blood cells. The tissue is matched to avoid rejection, but there is a risk of infection and only a few types of cells can be formed
What are meristems?
Meristems can differentiate into any plant cell type throughout the life of the plant. It is used to produce clones quickly and economically such as crop plants with disease resistance.
What are the three stages of cell division?
The three stages of cell division are growth, DNA synthesis and mitosis.
What occurs in the first stage of cell division? (growth)
In the first stage of cell division, there is an increased number of sub-cellular structures such as ribosomes and mitochondria
What occurs in the second stage of cell division? (DNA synthesis)
In the second stage of cell division, DNA is replicated to form two copies of each chromosome
What occurs in the third stage of cell division (mitosis)
In the third stage of cell division, The cytoplasm and cell membranes divide to form to daughter cells
