Cell Structure Topic 1a Flashcards
What is a Eukaryotic cell
- Complex cell including animal plant and fungi
- Contains membrane bound organelles
What is a prokaryotic cell
Prokaryotic cells are small simple cells e.g Bacteria
Name the subcellular structures that make up an animal cell
Nucleus - Contains DNA that controls the cell activity
Cytoplasm - gel like substance where chemical reactions take place
Cell membrane - semi permiable membrane that controls what goes in and out of the cell
Mitochondria - responsible for energy production through aerobic respiration
Ribosomes - responsible for Protein synthesis
Name three things a plant cell usually has that an animal cell dosent
Cell wall - rigid structure made of cellulose that is responsible for the structure of the cell
Vacuole - Contains cell sap (Sugar and salt solution)
Chloroplasts - responsible for photosynthesis the process which makes food for the plant. Contains chlorophyll a green substance which absorbs the light needed for photosynthesis
What sub cellular structures does a bacterial cell contain
Cell wall Cell membrane Cytoplasm Plasmid - small ring of DNA Circular strand of DNA that floats freely in the cytoplasm
What is a specialised cell
A specialised cell is a cell that has differentiated in order to perform a specific function
What is cell differentiation
Cell differentiation is the process by which a cell changes to become specialised for its specific job
TIP In most animal cells the ability to differentiate is lost after the cell has become differentiated, whereas most plants cells never lose this ability
What is an undifferentiated cell
Undifferentiated cells are stem cells and have the ability to differentiate into types of cell or simply replicate to produce more undifferentiated cells
What is the function of the sperm cell
The function of the sperm cell it to get the male DNA to the female DNA.
It is specialised for reproduction
- streamlined head
- lots of Mitochondria to provide the cell the energy to swim
- long tail for locomotion
- digestive enzymes to digest the cell membrane of the female egg
What is the function of the nerve cell
To carry electronic signal around the body
They are specialised for rapid signaling
- long to cover more distance
- Have branched connections at their ends to connect to other nerve cells and form a network through the body
What is the function of a muscle cell
The function of the muscle cell is to contract quickly. It is specialised for contraction.
- long in shape so they have space to contract
- contain lots of Mitochondria in order to produce the energy needed for contraction
What are root hair cells
Cells on the surface of plant roots that are specialised for absorbing water and minerals
- long hairs that stick out into the soil
- give the plant a bigger surface area for absorbing water, minerals and ions from the soil
Give one place where stem cells can be found in adult humans
Human bone marrow. These type of stem cells are already differentiated and can only turn into to certain types of cell such as blood cells
What use can be given for embryonic stem cells
Embryonic stem cells can be used to replace faulty cells in sick people
- Replace damaged nerve cells in people who are paralysed
- create new insulin producing cells to replace faulty cells in people who have diabetes
What is therapeutic cloning
Therapeutic cloning is a type of cloning where embryos are made to have the same genetic information as the patient.
Advantages
- stem cells have the same genetic make up as the patient so they would not be rejected by the body if used to replace faulty cells
What are the issues regarding the use of embryonic stem cells in medcine
Some people feel human embryos shouldn’t be used for experiments as each embryo still has the potential for life and obtaining stem cells from an embryo destroys the embryo
What are red blood cells
Red blood cells
- transport oxeygen around the body
- They have a bioconcave shape to give them a large surface area for absorbing oxeygen
- contain haemoglobin a red pigment which carries oxygen
- do not have a nucleus allowing more room for haemoglobin so they can carry more oxygen
What are chromosomes made of
Chromosomes are made of long lengths of DNA coild up to form the arms of the chromosome
Where in a cell are chromosomes found
Chromosomes are found in the cell nucleus
What are genes
Units of hereditary information that control our characteristics
What is mitosis
Mytosis is the process in which a cell reproduces itself by splitting to form 2 identical cells
Give two uses for mitosis in animals
Growth and replication of damaged cells
Describe the process of mitosis
- Chromosomes line up across the cenre of a cell and are pulled apart by cell fibres. Two arms of each chromosome go to opposite ends of the cell
- membranes for around each of the sets of chromosomes the nucleus has divided
- the Cytoplasm and cell membrane divide and two new daughter cells are produced, they are identical
What is binary fission explain what happens during this process
Binary fission is the process by which bacteria replicate
- circular strands of DNA and plasmids replicate
- DNA strands move to opposite ends of the cell (opposite poles)
- Cytoplasm begins to divide and a new cell wal begins to form
- Cytoplasm divides and 2 new daughter cells are formed. Each daughter cell has one copy of DNA but can vary in the number of copies of plasmids
How quickly can bacteria divide given the right conditiins
Every 20minutes
Warm environment with lots of nutrients
What is a culture medium
A culture medium is a place where bacteria is grown and contains carbohydrates vitamins and minerals needed for bacteria to grow
Give two kinds of culture medium
- Solid ager jelly in a petri dish
- nutrient broth
In a lab at school what temperature are cultures of microorganisms kept at and why
25°c and below
Harmful pathogens are likely to grow at above 25°c
How would you investigate the effects of antibiotics on bacterial growth
- place paper plates soaked in different antibiotic solutions on an ager plate with an even spread of bacteria
- the antibiotic solution will diffuse into the ager jelly. Antibiotic resistant bacteria will continue to grow but the non resistant strains will die
- a clear area will be left around the bacteria where the bacteria has died (INHIBITION ZONE)
What is the formula for calculating the area of inhibition zone
Area = 3.14 x radius squared
Example the diameter (distance across) of a inhibition zone is measured at 14mm
To find the radius ÷ by 2
14mm ÷ 2 = 7mm
3.1 x 7squared = 154mm squared
What is the purpose of a control disc
It shows that the lack of growth around the antibiotics disc is due to the antibiotics and not something else
How do you convert millimetre to micrometre
X1000
How do you find the real size of an object
Real size = image ÷ magnification
Name and explain the different phases of mitosis IPMAT(C)
Interphase - period of growth in which DNA synthesises (squiggly DNA in first diagram decondensed)
Prophase - chromatin condenses into chromosomes (x shape chromesomes in diagram)
Metaphase - Chromosomes line up at the center of the cell and mitotic spindles attach to them
Anaphase - Chromosomes are pulled apart to opposite poles of the cell
Telephase - two new nuclei form and chromosomes begin to decondense
Cytokinesis - Cytoplasm divides to form two new daughter cells (CONTAINING SQUIGGLY DNA DECONDENSED)
What is a gene
A unit of heredetery information
What is DNA
Long chained double stranded molecule
What is a nucliatide
It is a complete unit of phosphate sugar and base pair
What are the base pairs
Adenine
Thymine
Cytosine
Guanine
Describe the process of therapeutic cloning
a body cell is removed from a patient and an egg cell is taken from a donor
the nucleus is removed from the (donor) egg cell and discarded
the nucleus is taken from the patient’s cell
the nucleus is transferred to the donor cell
the resulting embryo is stimulated to divide
the embryo is cultured for 4-5 days
stem cells can then be removed and cultured
