Cell Biology Flashcards
Eukaryotic cells are…
…large, complex organisms
(Plant and animal cells)
What organelles do plant cells have
Cells wall
Nucleus
Cell membrane
Vacuole
Chloroplast
Mitochondria
Cytoplasm
Ribosomes
What organelles do animal cells have
Nucleus
Cell membrane
Mitochondria
Cytoplasm
Ribosomes
Prokaryotic cells are…
…non-complex organisms
(Bacteria)
What organelles are in bacteria cells
Ribosomes
Loose chromosomal DNA
Cell wall
Cytoplasm
Plasmid DNA
Cell membrane
Flagellum
Functions of the nucleus
Controls the cell and stores DNA
Functions of the cytoplasm
Carry out chemical reactions and hold organelles in place
Functions of the ribosomes
Carry out protein synthesis
Functions of the chloroplasts
Carry out photosynthesis
Functions of the cell membrane
Controls what enters and exits the cell
Functions of the cell wall
Supports and protects the cell
Functions of the vacuole
Stores sugars/water and salt. Turgid shape
Functions of the mitochondria
Carry out respiration which releases energy
What is DNA
The molecule in the cell that stores genetic information
What is a gene
A short section of DNA found in a chromosome that controls the development of 1 characteristic
What is a chromosome
A long strand of DNA that contains many genes
How many pairs of chromosomes are there in 1 cell
23
Except red blood cells and sperm/egg cells where the pairs are separated
What chromosomes do men have
X and Y
What chromosomes do women have
X
Equation for mitosis stage length
Length of stage = number of cells in stage (divided by) total number of cells
X length of cell cycle
Stage 1 mitosis
- The cell grows, producing more mitochondria and ribosomes
- The DNA replicates (interphase)
Stage 2 mitosis
- The chromosomes line up in the centre of the cell
- They get pulled to opposite sides of the cell
Stage 3 mitosis
- The cell membrane and cytoplasm divide (cytokinesis)
- Two genetically identical daughter cells are produced
What substances are diffused through cells
Carbon dioxide
Glucose
Oxygen
Amino acids
Definition of diffusion
The movement of particles from an area of higher concentration to an area of lower concentration
What factors is diffusion affected by
Surface area
Concentration gradient
Temperature
(Not energy - passive process)
Large surface area…
…increases space available for exchange
Large blood supply…
…maintains steep concentration gradient
Thin walls…
…short diffusion pathway/distance
Equilibrium meaning
No net movement, equal concentration
Isotonic meaning
Same concentration of solute as inside the cell
Hypertonic meaning
Higher concentration of solutes inside the cell
(Shrinks/shrivels)
(Plants plasmolysis)
Hypotonic meaning
Lower concentration of solute inside the cell
(Expands/bursts)
(Plants become rigid)
Osmosis definition
The diffusion of water particles from an area of high water concentration to an area of low water concentration across a partially permeable membrane
Is energy required for osmosis
No it’s a passive process
Definition of active transport
When molecules move from an area of low concentration to an area of high concentration against the concentration gradient
What does active transport require
Energy
Protein carrier molecule
What factors affect active transport
Temperature
Surface area
Oxygen availability (respiration)
What do root hair cells absorb through active transport
Mineral ions
What do villi absorb through active transport
Glucose
What do you use to place a cell on a microscope slide
Forceps
What do you stain microscope slides with
Iodine
Which objective lens do you start with on a microscope
Lowest magnification
What does the course focus wheel do on a microscope
Raises the stage
What does the glass slide do on a microscope
Prevents the specimen from dying out
What is the equation for magnification
I =AM
I - image size (mm)
A - actual size (um)
M - magnification
How do you convert from mm to um
Multiply by 1000
What does the head of a sperm call contain
Genetic material
What does the acromosome in a sperm call contain
Enzymes to penetrate an egg
What is the middle piece of a sperm full of
Mitochondria for energy
Why does a nerve cell have branches (dendrites)
To communicate with other nerve cells, muscles and glands
Why is the nerve cel covered in a fatty sheath
Insulates
Speeds up nerve impulse
Why does a root hair cell have a large surface area
For fast osmosis with more contact to the soil water
What to muscle cells contain that allow contraction
Filaments of protein that can Slide over each other
Why do phloem cells have companion cells
Because they have no mitochondria so use the mitochondria in the companion cells for energy
What are xylem cell walls thicken with
Lignin
What are stem cells
Cells that have not yet become specialised cells
What can bone marrow stem cells differentiate into
Blood and immune system cells
Where does cell division in plants occur
The meristems
