Biology Flashcard 2 - pathogens, DNA, cells, microscopes
What causes these:
1). Measles
2). Salmonella
3). Rose black spot
4). Malaria
- Viruses
- Bacteria
- fungi
- protist
What are the pros and cons of vaccines?
pros: - protection from diseases
- control of common diseases
- prevents outbreaks
cons:
- don’t always work
- bad reactions
What does unspecialised mean?
What are these cells called?
Each one of them can become any type of cell that is needed
- Stem cells
What is the name of the process of them becoming specialised
Differentiation
Why do cells need to divide (Three)
To repair damaged or worn out cells
To grow (e.g. bones or muscles)
asexual reproduction - some organisms clone themselves.
What is a section of DNA called
A gene
What is DNA packed into?
Chromosomes
What are the last two chromosones
A). male
B). Female
- XY
- XX
How many chromosomes do humans have?
23 pairs
What does DNA stand for?
Deoxyribonucleic acid
What is active transport? What does it do?
The movement of molecules across different cell membranes
Active transport moves substances from a dilute solution to a more concentred solution
Name a difference between diffusion and active transport
Active transport needs energy to move up and down the concentration gradient whereas diffusion doesn’t need any
What is osmosis?
Osmosis is the movement of water from an area of high concentration to an area of low concentration via a semipermeable membrane
What is a partially permeable membrane?
Barrier that lets small particles through but not the bigger particles
What is the definition of diffusion
Diffusion is the net movement of particles from high C to low C
Examples of diffusion in living organisms: (Two)
- Oxygen moves from high C in the alveoli to low C in the blood
- CO2 moves from high concentration in the blood to a low concentration in the alveoli
How is a sperm cell adapted to its function (Three)
- Long tail for swimming
- Large nucleus for chromosomes
- Many mitochondria to release energy that the cell needs to swim
How is a muscle cell adapted to its function (Two)
- They store glycogen which can be broken down into glucose (for exercise)
- They have many mitochondria for energy
List all the functions of the components of a cell (Eight)
- Nucleus (controls the cell and contains all the DNA for the cell)
- The cytoplasm is where all the chemical reactions are
- The cell membrane (this controls what enters and leaves the cell)
- Mitochondria - generates chemical energy
- Ribosomes - to make proteins (protein synthesis)
- cell wall - made of cellulose and forms shape of the cell
- Chloroplasts - contains chlorphyll for photosynthesis
- vacuole - gives structure to the cell and contains cell sap
What are the differences between a Eukaryotic and Prokaryotic? (Three)
- Prokaryots are unicellular and Eukaryots are multi cellular
- E are a lot bigger
- P don’t have a nucleus
What is resolving power?
Resolution is how well the microscope distinguishes between two points that are close together
What are the three types of microscopes?
- Light microscope
- Scanning electron
- Transmission electron
What are the advantages of a light microscope and how does it work
They are cheap and can be used anywhere
They use a beam of light to form the image
What are the advantages of an electron microscope and how does it work
Use a beam of electrons
Give 2D images and higher resolution
What are the three stages of cell division
- One: cell grows bigger, clones its DNA to form two copies of each chromosome
- Two: Mitosis - the nucleus divides into two
- Three - cytoplasm divides into two new identical cells.
What are the steps of mitosis (Five)
-( A body cell contains two pairs of chromosomes)
- Chromosomes duplicate
- All line up on the equator of the cell
- Chromosomes separate
- Cells split into two identical cells
What is homeostasis
The conditions inside your body are known as its internal environment and this needs to be controlled carefully
What is the nervous system made up of (Three)
- Brain
- Spinal cord
- nerves
