Cell Biology Flashcards
(19 cards)
Subcellular structures of an animal cell
•Nucleus - contains genetic material, controls the activity of the cell.
•Cytoplasm - where chemical reactions happen.
•Cell membrane - hold cell together, controls what goes in and out.
•Mitochondria - where most the reaction for aerobic respiration take place.
•Ribosomes - where proteins are made in the cell.
Subcellular structures in a plant cell
• Nucleus - contains genetic material, controls the activity of the cell.
•Cytoplasm - Where chemical reactions take place.
• Ribosomes - where proteins are made.
• Mitochondria - where aerobic respiration takes place, provides energy the cell needs to work.
• Cell membrane - holds the cell together, controls what goes in and out.
• Cell wall - made of cellulose, supports and strengthens cell.
• Chloroplasts - where photosynthesis occurs which makes food for the plant. Contain chlorophyll which absorbs light.
• permanent vacuole - contains cell sap, a weak solution of sugar and salts.
Formula for magnification
Magnification = image size -divided by- real size
Microscopy required practical
- preparing slide
•add drop of water to the middle of clean slide.
•cut up onion and separate it into layers. Use tweezers to peel off some epidermal tissue from bottom of one of the layers.
•using tweezers place epidermal tissue into water on the slide
•Add drop of iodine solution
• Place cover slip
Microscopy required practical
- using microscope
• clip slide onto stage.
• select lowest-powered objective lens.
• use coarse adjustment knob to move stage up below the lens.
• look down eyepiece and use adjustment knob to move stage until roughly in focus.
• if needed to view with greater magnification, swap to highest powered objective lens and refocus.
How are sperm cells specialised for their function?
Sperm cells are specialised for reproduction.
•function is to get the male DNA to the female DNA
•has long tail and streamlined head to help it swim to egg.
•Lost of mitochondria in cell to provide lots of energy needed
•carries enzymes in head to digest through the eggs cell membrane
How are nerve cells specialised for their function?
Nerve cells are specialised for rapid signalling.
•function is to carry electrical signals from one part of the body to another.
•Cells are long to cover more distance and have branched connection to connect to other nerve cells and form a network through ought the body
How are muscles cells specialised for their function?
Muscle cells are specialised for contraction
•the function of a muscle cell is to contract quickly.
•Cells are long so they have space to contract.
•Contain lots of mitochondria to generate the energy needed for contraction.
How are root hair cells specialised for their function?
Root hair cells are specialised for absorbing water and minerals.
•root hair cells are cells on the surface of plant roots, which grow into long “hairs” that stick out into the soil.
•this gives plants a big surface area for absorbing water and minerals.
How are phloem and xylem cells specialised for their function?
Phloem and xylem cells are specialised for transporting substances
•Form tubes, which transport substances such as food and water around plants.
•To form the tubes the cells are long and joined end to end.
•Xylem cells are hollow in the centre and phloem cells have very Subcellular structures, so stuff can flow through them.
What is diffusion?
Diffusion is the spreading out of particles from an area of higher concentration to an area of lower concentration.
• happens in solutions and gases - particles can move around freely
What is osmosis?
Osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
What is a partially permeable membrane?
A membrane with very small holes in it. So small on tiny molecules like water can pass through them and bigger molecules like sucrose cant.
What is cell differentiation?
Differentiation is the process by which a cell changes to become specialised for its job.
What are chromosomes?
•Chromosome are coiled up lengths of DNA molecules.
•Chromosomes contain genetic information
•Each chromosome carries a large number of genes
What type of molecules move by osmosis?
Water molecules.
What is the cell cycle?
The cell cycle makes new cells for growth, development and repair
•body cells in multicellular organisms divide to produce new cells as part of a series stage called the cell cycle.
What is mitosis?
The stage of the cell cycle when the cell divides is called mitosis.
• multicellular organisms use mitosis to grow or replace cells that have been damaged.
What are the 2 main stages of the cell cycle?
Growth and DNA replication.
•in a cell that’s not dividing DNA is spread out in longer strings
•before division cell has to grow and increase amount of Subcellular structures such as mitochondria and ribosomes.
•it then duplicates it DNA - so there one copy of each new cell. DNA copied and forms x shaped chromosomes.
Mitosis
•The chromosomes line up at centre of cell and cell fibres pull them apart . The two arms of each chromosomes go to opposite ends of the cell.
•Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells - the nucleus has divided
• lastly cytoplasm and cell membrane divide
The cell has now produced network new daughter cells. The daughter cells contain exactly the same DNA - they’re identical. Their DNA is also identical to the parent cell
