Cells‼️ Flashcards
What are differences between a light microscope and an electron microscope?
light microscopes: inexpensive,low maintenance,lower magnification,lower resolution,image is coloured,live and dead specimens can be seen
electron: expensive,high maintenance,high magnification,high resolution,image is black and white, only dead and dried specimens can be seen.
What is the formula used to calculate the magnification of an image?
magnification= image size/actual size
A specimen is 50 μm wide in real life. Calculate the width of the image under a magnification of x100.Give your answer in mm.
5000 μm or 5mm
What colour is the lowest powered objective lens?
Red
What colour is the medium powered objective lens?
yellow
What colour is the highest powered objective lens?
Blue
What does MRS GREN stand for?
Movement,Respiration,Senses,Growth,Reproduction,Excretion,Nutrition
What is the cytoplasm?
Where most chemical reactions take place
What is the nucleus?
controls the activities of the cell and contains chromosomes made of coiled DNA molecules. The chromosomes are normally found in pairs.
What does the cell membrane do?
controls what comes in and out of the cell
What do ribosomes do?
They are the site of protein synthesis
What does the mitochondria do?
aerobic respiration
What does the cell wall do?
Gives the cell strength, it is made of cellulose
What does the vacuole do?
It contains sap and help support the shape of the cell
What does the chloroplast do?
contains chlorophyll which is needed for photosynthesis
What sub cellular structures are present ONLY in plant cells?
Cell wall,vacuole and chloroplast
What are eukaryotes?
Cells which are complex and made of many cells Eg: Animal and Plant cells.They have a nucleus where the DNA is found and other membrane bound organelles.
What are prokaryotes?
Cells which are much smaller and simpler than eukaryotes and are a single celled organism Eg: bacteria. DNA is not found in a nucleus and is circular
What are the differences between eukaryotic and prokaryotic cells?
Prokaryotic cells are much smaller than eukaryotes, prokaryotes have no membrane bound organelles,DNA is not in a nucleus in prokaryotes,prokaryotes have extra rings of plasma
What are archaea?
Microorganisms which are similar to bacteria in size and simplicity of structure but radically different in molecular organization.
What are extremophiles?
A microorganism, especially an archaean, that lives in conditions of extreme temperature, acidity, alkalinity, or chemical concentration.
What is magnification?
The ability of a lens or other optical instrument to enlarge the size of the optical image
What is the magnification of the low power objective lens?
x4
What is the magnification of the medium powered objective lens?
x10
What is the magnification of the high powered objective lens?
x40
What is the magnification of the eyepiece lens?
x10
I want to magnify a specimen by a total magnification of x400. What power lens do i use?
High powered lens
10 x 40 = 400
eyepiece mag x objective mag
If I want to turn 0.017 in to standard form, what do i do and what would it be?
Move the decimal place left or right
1.7x10^-2
What is differentiation?
The process by which a cell gains certain features needed for their function
What are sperm cells specialised for?
The function of a sperm is to get the male DNA to the female DNA. It has a long tail and a streamlined head to help it swim to the egg. There are a lot of mitochondria in the cell to provide the energy needed. It also carries enzymes in its head to digest through the egg cell membrane.
What are nerve cells specialised for?
The function of these cells are to carry electrical signals from one part of the body to another. These cells are long to cover more distance and have branched connections at their ends to connect to other nerve cells and form a network throughout the body
What are muscle cells specialised for?
The function of these cells are to contract quickly. These cells are long(so they have space to contract) and contain lots of mitochondria to generate the energy needed for contraction.
What are root hair cells specialised for?
The function of these cells are to absorb water and minerals. They are on the surface of plant roots, which grow into long ‘hairs’ that stick out the soil, This gives the plant a big surface area for absorbing water and mineral ions from the soil.
What are phloem and xylem cells specialised for?
The function of these cells are for transporting cells. They form phloem and xylem tubes which transport substances such as food and water around plants. To form the tubes, the cells are long and joined end to end. Xylem cells are hollow in the centre and phloem cells have very few sub cellular structures, so that stuff can flow through them
Where are embryonic stem cells found?
In human embryos which are 3-5 days old
Where are adult stem cells found
brain,eyes,blood,heart,bone marrow,skin,muscle basically everywhere
Where are umbilical stem cells found?
in the umbilical cord
What can embryonic stem cells differentiate into?
any type of cell
What can adult stem cells differentiate into?
The cell where the stem cells were found
What can umbilical stem cells differentiate into?
blood cells of all kinds
What are some pros to using embryonic stem cells?
They can be developed into any variety of cells,found in the body,not specialised,can be used for research or for medical reasons
What are some cons to using embryonic stem cells?
It requires the use of an embryo,potential ethical issues,immunosuppressants required(not for therapeutic),technology is still developing,expensive
Where are the stem cells found in a plant?
The meristem
What are benefits to using plant stem cells?
Clones made quickly and efficiently,economic benefit,medicinal properties,identical plants made for research,could prevent extinction,make crops with disease resistance
What is mitosis?
Cell division that results in genetically identical diploid cells and is important in the growth and development of multicellular organisms.
What parts of the cell cycle form the interphase?
G1, S, G2
What are the parts of the cell cycle?
prophase,metaphase,anaphase,tele-phase,cytokinesis,cell rest
What does the cell start as?
A parent cell,with 46 chromosomes, 23 from the father and 23 from the mother. The cell has 2 copies of each chromosome.
What happens in the interphase?
The DNA and the organelles duplicate, with each chromosome consisting of 2 sister chromatids. The cell then checks the duplicated chromosomes for error,making any needed repairs.
What happens in prophase?
The DNA condenses, becoming shorter and thicker and the nuclear membrane disappears. The centriole divides and move to
opposite poles of the cell and spindle fibres form between the centrioles.
What happens in metaphase?
The chromosomes line up on the equator of the cell and attach to spindle fibres by their centromeres.
What happens in the anaphase?
The chromatids joining the sister chromatids split due to the motor proteins along the spindle fibres in opposite directions.This pulls the chromatids,now chromosomes, to he pulled to opposite poles of the cell.
What happens in the telephase?
The separated chromosomes reach opposite poles and a nucleus envelops around the two sets of duplicated chromosomes. The two nuclei that form are identical to each other.
What happens in cytokinesis?
The cell membrane and cytoplasm divide to give two new daughter cells. Each daughter cell is genetically identical to parent cell and each other, with the same chromosome number.
What happens in G0 or cell rest?
The cell rests temporarily. Some cells will never divide again.
What is cell enlargement?
The increase in cytoplasmic volume, as in cell development and cell reproduction
What is binary fission?
Mitosis for bacteria
What sub-cellular structures are found in the animal cell?
Cytoplasm,cell membrane, nucleus, ribosomes and mitochondria
What do plasmids do in bacterial cells?
Plasmids are used to transfer the information from one cell to another,i.e., transfer of important genes
What is cell differentiation?
Cell differentiation is the process of a stem cell forming into a specialised cell.
