CELL BIOLOGY Flashcards
Eukaryotic cells are (structure and what it includes)
complex and include all animal cells
Prokaryotic cells are (eg…….)
smaller and simpler eg bacteria
Eukaryotes are made up of
eukaryotic cells
Prokaryotes are made up of and are
prokaryotic cells and are single celled organisms
Role of Nucleus
contains genetic material that controls the activities in the cell
Role of Cytoplasm
the cytoplasm is a gel like substance where most of the chemical reactions happens, contains enzymes which control these chemical reactions.
Role of Cell Membrane
controls the movement of
substances in / out of cell
Role of Mitochondria and what do they do
where most of the reactions for aerobic respiration takes place. they release energy
Role of Ribosomes
these are where proteins are made in the cell
what are subcellular structures
they are the different parts of the cell
what do plant cells have that animal do not
cell wall
permanent vacuole
chloroplasts
role of cell wall
made of cellulose, it supports the cell and strengthens it
role of permanent vacuole
contains cell sap
role of chloroplasts
- where photosynthesis occurs
- which makes food for the plants
- they contain chlorophyll
- which absorbs the light needed for photosynthesis
do bacterial cells have nucleus
no they have a single circular strand of DNA that’s floats freely in the cytoplasm
what other subcellular structure does a bacterial cell have that contains DNA
PLASMIDS
What are light microscopes used for
light microscopes use light to form an image and magnify it. they help us see individual cells and large subcellular structures eg. nuclei
What are electron microscopes used for
electron microscopes use electrons instead of light to form an image.
they have a higher resolution and magnification than a light microscope.
they help us see smaller things in more detail.
what is differentiation
is the process by which a cell changes to become specialised for its job
what happens when cells change ( differentiation)
they develop subcellular structures and turn into different types of cells
when does most differentiation occur
as an organism develops
differentiation in animal cells
most animal cells lose the ability to differentiate at an early stage after they become specialised
differentiation in plant cells
lots of plant cells do not lose the ability to differentiate
what are the cells that differentiate in mature animals used for?
they are used for repairing and replacing cells
what are sperm cells specialised for and how are they adapted?
Specialised for reproduction:
FUNCTION-TO GET MALE DNA TO THE FEMALE DNA
1. long tail and a streamlined head to help it swim to the egg
2. lots of mitochondria in the cell to provide energy needed.
3. carries lots on enzymes in its head to digest through the eggs cell membrane
what are nerve cells specialised for and how are they adapted
Specialised for Rapid signalling:
FUNCTION-they carry electrical signals from one part of the body to another
2.they are long and have branched connections at their ends, to connect other nerve cells and form a network throughout the body.
what are muscle cells specialised for and how are they adapted
Specialised for contraction
FUNCTION- TO CONTRACT QUICKLY
1. They are long so they have space to contract
2. They contain lots of mitochondria to generate the energy needed for contraction
what are root hair cells specialised for and how are they adapted
Specialised for absorbing Water and Minerals.
Root hair cells are cells on the surface of plant roots
1. grow into long hairs that stick into the soil- this gives the plant a large SA for absorbing water and mineral ions from the soil.
what are phloem and xylem cells specialised for and how are they adapted
Specialised for Transporting Substances
phloem and xylem cells form tubes which transport substances eg food and water around the plant.
xylem cells are hollow in the centre and transport water and minerals upwards
phloem cells have very few subcellular structures so substances can flow through they transport Products of photosynthesis; includes sugars and amino acids dissolved in water
chromosomes
coiled up lengths of DNA molecules
each chromosome carries a large number of genes -different genes control development of different characteristics
the events of the cell cycle that need to occur before mitosis begins
- in a cell that’s not dividing dna is all spread out in long strings
- before a cell divides the cell has to grow and increase the amount of sub cellular structures such as mitochondria and ribosomes
- It then duplicates its DNA- so theres one copy for each new cell.
mitosis
can occur when the its contents and dna have been copied
chromosomes line up at the centre of the cell and cell fibres pull them apart, the two arms of each chromosome go to the opposite ends of the cell
membranes form around each of the sets of chromosomes-these become nuclei of the two new cells
lastly the cytoplasm and cell membrane divide- the cell has now produced two new daughter cells,
binary fission
the way prokaryotic cells replicate:
the circular DNA and plasmids replicate
the cell gets bigger and the circular DNA strands move to opposite ends of the cell
the cytoplasm begins to divide and new cell wall begin to form.
the cytoplasm divides and two daughter cells are produced.
each daughter cell has one copy of the circular DNA but can have a variable number of copies of the plasmids
conditions that affect binary fission
warm environment
lots of nutrients
differentiation
is the process by which a cell changes to become specialised for its job
what are undifferentiated cells
these are called stem cells, they can divide to produce lots more undifferentiated cells. They can differentiate into different types of cells depending on the instructions given
where are stem cells found
in early human embryos
where are adult stem cells found
bone marrow
these stem cells cannot turn into any cell
what can stem cells be used for in medicine
stem cells can be grown in the lab to form clones and can be made to differentiate into specialised cells to use in medicine or research
