4.1 Cell Biology Flashcards
What are cells?
The basic unit of all forms of life
What is the difference between prokaryotic and eukaryotic cell’s ?
Eukaryotic cells have a nucleus and prokaryotic cells dont
What are the properties of prokaryotic cells?
Cell membrane,slime capsule,cell wall, plasmids,flagella,genetic material,cytoplasm,cell membrane
What is a muscle cell?
Muscle cells are specialised cells that can contract and relax in pairs to move the bones of the skeleton
What are striated muscle cells?
They are striped muscle cells
What is a smooth muscle cell?
They form one of the layers of tissue in your digestive system and they contract to squeeze the food through your gut
What are the main adaptations of muscle cells?
-contain special proteins that slide over each other making the fibres contract
-contain many mitochondria to transfer energy needs for the chemical reactions that take place as the cells contract and react
-can store glycogen (a chemical that can be broken down and used in cellular respiration)
What is a sperm cell?
The male sex cells or gamete’s that contain the genetic material from the parent
What are the adaptations of sperm cells ?
A long tail whips side to side to help move the sperm through water or the female reproductive system
The middle section contains lots of mitochondria to provide the tail energy to work
A large nucleus contains the genetic information to be passed on
The acrosome stores digestive enzymes for breaking down the outer layer of the egg
What are nerve cells?
Nerve cells are specialised to carry out electrical impulses around the body of an animal
What are the adaptations of nerve cells?
Lots of dendrites to make connections with other cells
A long axon that carries the nerve impulses from one place to another
The synapses pass impulses to another cell or between a nerve cell and a muscle using special transmitter chemicals
Contains lots of mitochondria to provide the energy needed to make transmitters chemicals
What are dendrites?
Branches of a nerve cell
What are root hair cells?
Root hair cells help take up water and mineral ions more efficiently
What are the adaptations of root hair cells?
They increase the surface area available for water to move into the cell
They have a large permanent vacuole that speeds up the movement o water by osmosis from the soil across the root hair cell
They have mitochondria that transfer the energy needle for the active transport of mineral ions into the root hair cells
What are photosynthetic cells?
What are the adaptations of photosynthetic cells?
They contain chloroplast containing chlorophyll that trap the light needed for photosynthesis
They are positioned in continuous layers in the leaves and outer layer of the stem so they absorb as much light as possible
They have a large permanent vacuole that helps keep the cell rigid as a result of osmosis
What are xylem cells?
Xylem is the transport tissue in plants that carries water and mineral ions from the roots to the highest leaves and shoots
What are the adaptations of xylem cells?
Xylem cells are alive when first formed but a special chemical called lignin builds up in spirals in the cell walls , the cells then die and form long hollow tubes that allow water and mineral ions to move easily through them
The spirals and rings of lignin make the cell very strong and help withstand the pressure of water moving up the plant it also helps support the plant stem
What are phloem cells?
Phloem is the specialised transport tissue that carries the food made by photosynthesis around the body of the plant
What are the adaptations of phloem cells?
The cell walls break down to form sleeve plates , this allows dissolved food to move freely up and down to where it is needed
Phloem cells are supported by companion cells that help keep them alive ,the mitochondria of the companion cells transfer the energy needed to form the dissolved food to move up and down
What are adult stem cells?
They replace damaged or dead cells that couldn’t be divided
What is a gene?
A small packet of information that’s controls a characteristic or part of a characteristic of your body
What are chromosomes?
Chromosomes carry the genes that contain the instructions for making new cells
What is mitosis ?
A process in the cell division cycle that produces 2 identical cells
Describe stage 1 in the cell cycle
The cell grows and increases the number of sub cellular structures such as ribosomes and mitochondria.the dna then replicates and forms 2 copies of each chromosome
Why is cell division by mitosis so important?
Mitotic cell division is important in the growth, repair and development of multicellular organisms
Describe stage 2 in the cell cycle
Stage 2 is mitosis and one set of chromosomes is pulled to each end of the cell and the nucleus divides
Describe stage 3 in the cell cycle
In stage 3 the cytoplasm and cell membranes divide to form 2 identical daughter cells
What is a zygote
When the egg and sperm fuse
What is a stem cell?
An undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type and from which certain other cells can arise from differentiation
What are adult stem cells?
Stem cells that are found in adults that can differentiate and form a limited number of cells
What does the nucleus contain
Chromosome made of dna molecules
How many chromosomes are there
46 chromosomes 23 pairs
What is a stem cell?
An undifferentiated cell
What is the function of a stem cell?
To repair and replace dead or damaged cells
What are the types of stem cells ?
Embryonic and adult stem cells in animal cells and meristems in plant cells
What can embryonic stem cells form
Then can be cloned and can differentiate into most different types of human cells
What can adult stem cells form?
What can meristems form?
They can differentiate into any type of plant cell through the life of the plant
What can stem cells treat?
Diabetes and paralysis
What are the pros in meristems ?
Used to make clones of plant’s quickly and economically
Rare species can be cloned to protect from extinction
Can clone crop plants with special features such as disease resistance
What are the effectiveness of an exchange surface increased by?
Large surface area
Thin membrane for a short diffusion path
An efficient blood supply
Being ventilated
How are the gills in fish adapted for exchanging materials?
They are made up stacks of thin filaments each with a rich blood supply
Need a a constant flow of water to maintain concentration gradient needed for gas exchange
Get a constant flow of water by pumping water over the gils
How are the roots and adapted for exchanging materials?
Have large surface area to make the uptake of mineral and water more efficient
Water constantly moving away from the roots maintaining a steep concentration gradient
How are the lungs and small intestine adapted for exchanging materials?
Alveoli have an enormous surface area and are rich in blood supply for effective gas exchange
The villi of the small intestine also have a large surface area short diffusion paths and a rich blood supply to make exchof materials more effective
How are the leaves of plants adapted for exchanging materials?
Flat thin leaves , the presence of air spaces in the leaf and the stomata all help provide a big surface area and maintain a steep concentration gradient for the diffusion of substance
What does active transport absorb?
It allows mineral ions to be absorbed into plant root hair cells
Allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has higher sugar concentration
Sugar molecules are used for respiration
