B1 Cell Biology Flashcards
What is the role of the nucleus?
Contains DNA/ genetic information. Controls the cell’s activities.
What is the role of the mitochondria?
Where respiration takes place to release energy.
What is the role of the cell membrane?
Controls the movement of substances in/out the cell. (selectively permeable).
What is the role of the cytoplasm?
Where chemical reactions take place.
What are the role of ribosomes?
Where protein synthesis takes place.
What is the role of chloroplasts?
Absorb light for photosynthesis. Contain a green pigment called chlorophyll.
What is the role of the vacuole?
Keeps the cell rigid. Filled with cell sap.
What is the role of the cell wall?
Strengthens and supports the cell. Made of cellulose.
How big is a plant cell?
10-100 micrometers
How big is an animal cell?
10-30 micrometers
What organelles are in a plant cell?
Cell wall, cell membrane, vacuole, chloroplasts, cytoplasm, ribosomes, mitochondria, nucleus
What organelles are in an animal cell?
Cell membrane, nucleus, cytoplasm, ribosomes, mitochondria
What type of cell are plant and animal cells?
Eukaryotic
What is an eukaryote?
A cell with a nucleus
What is a prokaryote?
A cell without a nucleus.
What is a prokaryote example?
Bacteria
What are eukaryote examples?
Plants, animals, fungi, Protista
How big is a bacteria cell?
0.2-2 micrometers
What is in a bacteria cell?
Cell membrane, slime capsule, cell wall, plasmids, flagella, cytoplasm, genetic material.
What is a light microscope?
A light microscope uses a series of lenses and an incident ray of light to produce a magnified image of the object being used.
What is an electron microscope?
An electron microscope uses a beam of electrons over a specimen to produce a magnified image of an object.
What is magnification?
The degree to which an image is made to appear bigger.
What is resolution?
The smallest interval measurable between two points on an image.
What are benefits of light microscopes?
Small, portable, images can be viewed in colour, cheaper, easier to use.
What are limitations of light microscopes?
Lower resolution, lower magnification.
What are benefits of electron microscopes?
Higher magnification, higher resolution.
What are limitations of electron microscopes?
Very large, cannot view live samples, can only view in black and white, expensive.
Image size = ?
Actual size X Magnification
What is the function of a palisade cell?
To maximise photosynthesis,
How are palisade cells adapted?
They contain specialised green structures called chloroplasts called chlorophyll that trap light. They are positioned in continuous layers in leaves, and outer layers of the stem of a plant to absorb as much light as possible.
What is the function of a root hair cell?
Takes up water and mineral ions more effectively.
What are the adaptations of a root hair cell?
Large surface area available for water to enter the cell. Large permanent vacuole.
What is the function of a sperm cell?
To fertilise the egg and provide the genetic information from the male.
What are the adaptations of a sperm cell?
A long tail that whips from side to side helps the sperm move. The middle section is full of mitochondria, which transfer energy from the tail to help it work. The acrosome stores digestive enzymes for breaking down the outer layer of the egg.
What is the function of the nerve cell?
Carry electric impulses around the body of an animal.
What are the adaptations of a nerve cell?
Lots of dendrites to make connections to other nerve cells. An axon that carries the nerve impulse from one place to another.
What is the function of red blood cells?
To transport oxygen around the body. Oxygen is required for respiration.
What are the adaptations of red blood cells?
Large surface area, biconcave shape, small and flexible in shape to fit through blood vessels.
What is differentiation?
The process when cells become specialised at different points during development, giving them certain features.
What are some examples of specialised plant cells?
Palisade cell, Xylem cell, Phloem cell, Guard cell, Root hair cell
What are some examples of specialised animal cells?
Red blood cell, sperm cell, egg cell, nerve cell, muscle, ciliated epithelial cell.
What are stem cells?
The first type of cells in a human embryo, differentiation happens at an early stage, once decided cannot change.
What are meristem cells?
First type of cells found in root tips in plants. They can differentiate at any time and can also redifferentiate.
What are advantages of embryonic stem cell research?
Provides hope and treatment for paralysis and Parkinson’s Disease
What are disadvantages of embryonic stem cell research?
Personal and religious beliefs, funding and time for patient.
Where are stem cells usually found?
In bone marrow.
What is a cell?
The basic building block of a living organism.
What is a tissue?
A group of cells with similar structure and function working together.
What is an organ?
A group of different tissues working together to carry out a specific function.
What is an organ system?
A group of organs working together to perform specific functions.
What are the 3 main types of tissue?
Muscle, glandular, epithelial
What is muscle tissue?
Contracts to allow movement.
What is glandular tissue?
Produces hormones/ enzymes.
What is epithelial tissue?
Lines the surface of organs for protection.
What is binary fission?
The process by which prokaryotic cells change their functional or phenotypical type.
How do you prepare an uncontaminated culture?
- Sterilise the inoculating loop used to transfer micro- organisms to the agar by heating it until it is red hot in the flame of a Bunsen and then letting it cool. Do not put the loop down or blow on it as it cools.
- Dip the sterilised loop in a suspension of the bacteria you want to grow and use it to make zigzag streaks across the surface of the agar. Replace the lid on the dish as quickly as possible to avoid contamination.
- Fix the lid of the Petri dish with adhesive tape to prevent microorganisms from the air contaminating the culture – or microbes from the culture escaping. Do not seal all the way around the edge – as oxygen needs to get into the dish to prevent harmful anaerobic bacteria from growing.
- The Petri dish should be labelled and stored upside down to stop condensation falling onto the agar surface.
What is mitosis?
Mitosis is a type of cell division in which a diploid body cell copies itself and finally divides into two identical diploid daughter cells. The daughter cells are clones of each other. Every base pair of their DNA is identical.
What are the different stages of mitosis?
Interphase - The cell spends most of its life in this phase. The DNA in chromosomes copies itself ready for mitosis.
Prophase - The DNA in chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears.
Metaphase - Chromosomes and their copies line up in the middle of the cell.
Anaphase - Chromosomes and their copies are pulled to different ends of the cell.
Telophase - New membranes form around the chromosomes at each end of the cell.
Cytokinesis - The cell membrane pinches in and eventually divides into two daughter cells.
What is diffusion?
The random movement of a substance from a high concentration to a low concentration.
What is active transport?
Requires energy. Moves a substance across the concentration gradient from an area of low concentration to an area of high concentration.
What is osmosis?
Osmosis is the diffusion of water molecules from a dilute solution (high concentration of water) to a more concentrated solution (low concentration of water) across a selectively permeable membrane . By doing this, water moves down the concentration gradient .
What factors affect the rate of diffusion?
Temperature
Surface Area
Distance
Concentration gradient
Does a single-celled organism have a high or low surface area to volume ratio?
High
What factors make an exchange surface more effective?
Large surface area
Short diffusion distance
Good blood supply
Moist
What does hypertonic mean?
This solution is concentrated (little water)
What does hypotonic mean?
This solution is very dilute (lots of water)
What does isotonic mean?
There is no difference in concentration and the movement of water remains constant.
What is the isotonic point?
Everything involved is the same concentration
Examples of substances moved by diffusion
Carbon dioxide, oxygen, water, food substances, urea
Examples of substances moved by osmosis
Water
Examples of substances moved by active transport
Mineral ions, glucose
What is a partially permeable membrane?
A membrane that only lets certain particles or ions through
