B1-Cell Biology Flashcards
What is in an animal cell?
Nucleus,Cytoplasm,Ribosome’s,
Mitochondria,Cell Membrane
What does the nucleus contain?
Genetic material
What happens in the cytoplasm?
Where most chemical reactions happen
What happens in the Ribosomes?
Proteins are made
What happens in the mitochondria?
Where most of the reactions for aerobic respiration take place
What does the cell membrane do?
Controls what comes in and out of the cell
What is in a plant cell?
Chloroplast,cell wall , vacuole, mitochondria,nucleus,cell membrane, cytoplasm,
What happens in the chloroplasts?
Photosynthesis occurs
What does a vacuole contain?
Cell sap
What is the cell wall made of?
Cellulose which strengthens the cell
What is in the bacteria cell?
Cell wall, cell membrane, plasmid, DNA loop floating in cytoplasm
What is a plasmid?
Small ring of DNA
Were electron microscopes invented before of after light microscopes?
After
What microscopes has a higher resolution and magnification?
Electron
What is the formula for magnification?
Image size/real size
What is a chromosome?
Coiled up lengths of DNA molecules, which carry genes. They’re found in the nucleus, and they’re normally in pairs in body cells.
What is the cell cycle?
A series of stages in which cells divide to produce new cells.
Before a cell divides what 3 things does it do?
- Grows in size
- Increases the amount of sub cellular structures, e.g mitochondria and ribosomes
- Duplicates it’s DNA
What is mitosis?
The stage of the cell cycle when the cell divides
What happens during mitosis?
a single cell divides into two identical daughter cells. This ensures that each daughter cell has the same genetic information as the parent cell.
What does mitosis allow multicellular organisms to do?
They allow them to grow or replace cells that have been damaged
What is Binary fission?
The simple process by which bacterial cells replicate. It can happen as often as every 20 minutes if there are enough nutrients and the temperature is suitable
What is cell differentiation?
the process by which cells become specialized to perform specific functions in an organism.
What are the five types of specialised cells?
Sperm cell, Muscle cell, Nerve cell, root hair cell, Xylem and phloem
What is the sperm cell and what does it do ?
It is a long tail and streamlined head for swimming to the egg. (Reproduction)
What is the muscle cell and what does it do?
It is long so they have space to contract and lots of mitochondria for energy.(contraction)
What is the nerve cell and what does it do?
It is long to cover a large distance, and branched to form a network of connections. (Rapid signalling)
What is the root hair cell and what does it do?
It is a large surface area for absorbing water and mineral ions from the soil. (Absorbing water and minerals)
What is Xylem and phloem and what does it do?
Xylem cells are hollow and phloem cells have few subcellular structures, so substances can easily flow through. (Transporting substances)
What are stem cells?
Undifferentiated cells, which can divide to produce lots more stem cells, and can differentiate into many other types of cell.
What can stem cells from an adult bone marrow become?
Many kinds of cell, e.g blood cells
What can stem cells from a human embryo become?
Any kind of human cell.
What can stem cells from a plant meristem become?
Any kind of plant cell
What is the use of stem cells in medicine?
Stem cells could produce nerve cells to test paralysis, or insulin-producing cells to treat diabetes
What is therapeutic cloning?
a process that produces an embryo with genes that are identical to the patient’s. Stem cells taken from this embryo will have the same DNA as the patient.
What is the risk of using stem cells in a lab?
The stem cells could get a virus which could get transferred to the patient
What is diffusion?
The spreading out of particles form an area of higher concentration to an area of lower concentration
What can diffuse through cell membranes?
Only very small molecules (e.g oxygen, glucose)
Which three factors increase the rate of diffusion across a cell membrane?
- A high concentration gradient (e.g loads of the particles on one side and hardly any on the other)
- High temperature
- Large surface area
What is osmosis?
The movement of water molecules across a partially permeable membrane form a region of higher water concentration to a region of lower water concentration.
What is active transport?
The movement of a substance against the concentration gradient. Unlike diffusion and osmosis, it requires energy from respiration.
What does active transport allow mineral ions to do?
It allows mineral ions (for plant growth) to be absorbed from the soil into the root hair cells
What does active transport allow glucose to do?
It allows glucose (for cell respiration) to be absorbed into the bloodstream from the gut
What does a single-celled organism contain?
It has a large SA(surface area):vol ration. It has enough substance that can pass across outer surface to meet needs of organism
What does a multicellular organism contain?
A small SA(surface area):vol ratio. many cells far away from outer surface to get substances in and out this way ➡️ exchange surfaces and transport systems are needed so needs of every cell can be met.
What does exchange surfaces have?
- A large surface area (so lots can diffuse at once)
- A thin membrane ( for short diffusion distance)
- An efficient blood supply (in animals)
- Ventilation (in gas exchange in animals)
What organs are adapted for exchange?
Leaves, gills, alveoli , small intestine
What do the leaves do in gas exchange?
carbon dioxide enters and water vapour and oxygen leave the plant through the stomata.
What are the function of Gills during gas exchange?
Oxygen and carbon dioxide move between water and blood
What is lamellae?
a thin layer, membrane, or plate of tissue
What does the small intestine do?
Absorbs food molecules from gut to blood
What and where is the alveoli?
where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.
