Paper 1/ 2: Section 1- Key Concepts in Biology Flashcards
What is the difference between a prokaryotic cell and a eukaryotic cell?
A eukaryotic cell is multicellular and has a nucleus. Prokaryotic cells have no nucleus and are unicellular.
What subcellular structures (different parts of a cell) are ONLY in a plant cells and what are their functions?
- Cell wall- supports/ strengthens the cell.
- A large vacuole- contains cell sap which maintains the internal pressure (supporting the cell).
- Chloroplasts- where photosynthesis occurs.
What subcellular structures are in bacteria cells and what are their functions?
- Chromosomal DNA- controls cell activities/ replication.
- Ribosomes- protein synthesis.
- Cell membrane- holds cells toghether/ controls what goes in and out.
- Plasmid DNA- small loops of extra DNA.
- Flagellum (plural flagella)- movement away from danger and towards beneficial things.
What is a specialised cell?
Cells which are adapted to their function.
What are red blood cells function and how are they adapted to do so?
RBC’s contain a protein called hemoglobin which carries oxygen around the body.
What are sperm cells function and how are they adapted to do so?
Sperm cells transport the male’s DNA to the female’s egg.
. Long tail- to swim to the egg
. Mitochondria in the middle section- provides energy to swim.
. Acrosome at the front of the ‘head’- soes enzymes to digest through the egg cell membrae.
. Contains a haploid nucleus.
.
What are egg cells function and how are they adapted to do so?
Egg cells carry the female DNA and to nourish the early stages of the embryo.
. Nutrients in the cyptoplasm- to feed the embryo.
. Changes the structure after fertilisation- to prevent any more sperm getting in.
What are muscle cells function and how are they adapted to do so?
Muscle cells help a human being to make movements.
. Cylindrical cells formed of banded fibres that allow contraction.
What are ciliated epithelial cells function and how are they adapted to do so?
Ciliated epithelial cells move substances (like mucus).
. Cilia (hair- like structures)- push substances along the tissue surface in one direction.
What are root hair cells function and how are they adapted to do so?
Root hair cells enable a plant to absorb minerals and water.
. Large surface area- allows absorption of more water/ minerals.
. Lond and thin- able to penetrate between soil particles.
What is a stem cell and a meristem cell?
Stem cell- A cell with the potential to specialise.
Meristem cell- the name for plant stem cells.
What is a diploid cell?
A body cell with all chromosomes (23 pairs).
What is a haploid cell?
A gamete with half the body cells chromosomes.
What is the difference between a light microscope and a electron microscope?
Light Electron
microscope: microscope:
. Uses light . Uses
rays electron rays
. x2000 . x500,000
magnification
. Small and . Large
portable
. Cheaper . Expensive
What is resolution?
The clarity of an image.
How do you calculate magnification?
Magnification (M)= Image size (I) / Actual size (A)
What is the definition of optimum pH?
The ideal pH for an organisms enzyme.
What is the Lock and key model?
For an enzyme to work, a substrate has to fit ito the active site. If the substrate’s shape doesn’t fit then the reaction won’t be catalysed.
What does it mean for an enzyme to denature?
When the active site changes and the substrate no longer fits into it.
What three things affect the rate of reaction?
. Temperature
. pH
. Substrate concentration
How do you calculate the rate of reaction?
Rate= 1000/ Time
Which 3 essential nutrients does your body need?
. Carbohydrates
. Protein
. Lipids
How are these three large molecules broken down into smaller ones?
. Carbohydrates (starch), broken down by amalayse, makes glucose.
. Protein, broken down by protease, makes amino acids.
. Lipids, broken down by lipase, makes glycerol and fatty acids.
What is synthesis and enzymes role in synthesis?
Synthesis involves the linking together of large molecules smaller components in correct sequence.
. Some enzymes join these molecules toghether.
What is osmosis and does it require energy?
- Osmosis- Movement of water molecules across a permeable membrane, from a high to low water concentration.
- It doesn’t require energy.
Where does osmosis occur?
Water
What is osmosis’ effect on plant cells?
. Becomes turgid in a solution with a higher water potential.
. Cells become flaccid when in a lower water potential.
What is osmosis’ effect on animal cells?
. Heavier effect seeing as the have no cell wall.
. Can burst when the tissue fluid has a higher water potential.
. Cells can die when surrounded by a lower water potential.
What is diffusion and does it require energy?
- Diffusion- Movement of particles from a high to low concentration, across the concentration gradient.
- It doesn’t require energy.
Where does diffusion occur?
Fluids (liquids/ gases)
What is active transport and does it require energy?
- Active transport- Movement of particles from a low to high concentration, across the concentration gradient.
- It does require energy transferred during respiration.
Where does active transport occur?
In plants
What part does a protein molecule play in active transport?
Proteins embedded in the cell membrane (carrier proteins) help active transport.
