cells Flashcards
what does the cell membrane do
it surrounds contents of the cell and separates the cell from is external environment. it controls transportation coming in and out of the cell
what is intracellular fluid
fluid within the cell
what is extracellular fluid
fluid outside of the cell
what is diffusion (passive transport)
when substances move through the membrane down the concentration gradient
what is a solute
anything that dissolves in water. they try to equalise themselves and make the 2 sides of the membrane equal so they move down the concentration gradient
what is passive transport
transport through the membrane that requires no energy
what is active transport
transport through the membrane that requires energy, moves substances against their concentration gradient
types of passive transport
osmosis, diffusion via protein channels, diffusion via carrier proteins, simple diffusion, diffusion, facilitated diffusion, filtration
what is osmosis (passive transport)
water moves through the cell membrane from a low concentration to a high concentration (against the gradient) to try dilute the more substance side. requires no energy even though its going against the gradient
what is diffusion via protein channels (passive transport)
sodium ions move through a sodium channel down their concentration gradient
what is diffusion via carrier protein (passive transport)
amino acids move into a cell via a carrier protein, because there are less amino acids inside the cell
what is simple diffusion
solutes move through phospholipids
what is facilitated diffusion (passive transport)
solutes move through proteins (channels for small solutes and carriers for medium solutes)
what is filtration (passive transport)
water and solutes are forced through the membrane due to high pressure
what is vesicular transport (active transport)
large proteins move into the cell via endocytosis (substances from the exterior of the cell are wrapped in a small bit of plasma membrane) or out of the cell via exocytosis (vesicles within the cell bind to and fuse with the cell membrane, then release their contents outside of the cell)
what is active primary transport
ATP is used to change protein shape allowing it to pump the solutes across the cell membrane. the movement of sodium and potassium by the pump by the sodium/ potassium pump
what is secondary active transport
the energy used in primary transport is stored and able to be used to help other substances across the membrane against the concentration gradient via co transportation with sodium when sodium diffuses back across the cell membrane through co transporter. e.g movement of glucose against the gradient with sodium
what do protein pumps do
main method of active transport. they push solutes through the membrane against the concentration gradient. from low to high concentration
an example of a protein pump
the sodium and potassium pump. pumps and pushes them against their concentration as the primary step. it then attaches a glucose to the sodium as the as a secondary transport
what is the nucleus
the control centre of the cell. contains the genetic material of the individual which directs protein synthesis and therefore most other cellular processes and functions
what is the cytoplasm
a gel like substance in which numerous organelles are suspended.
job of the mitochondria
turns food into energy
job of the lysosomes
destroys debris and dead bits so cells function
job of ribosomes
where strands of RNA go to make protein
job of centrosomes
anchors the cytoskeleton, cilia and flagella
job of Golgi apparatus
modifies and packages proteins and lipids
what is the flagella
only found in one human cell, found in the sperm
what makes up the cell membrane
proteins, phospholipids, carbohydrates, cholesterol, glycolipids, glycoproteins
what is the phospholipid bilayer made of
the heads of the phospholipids are hydrophilic (like water) and the tails are hydrophobic (doesn’t like water)
what is protein synthesis
DNA and RNA
what is DNA
2 chains of nucleotides. They have 4 out of 5 bases (A,G,T,C). A and T are pairs and G and C are pairs. humans have 23 chromosomes. One length of the chromosome is from the mum and the other from the dad. the code of the DNA is for different protein which characterises what we look like
what is RNA
it is a single strand of nucleotides. They have 4 out of 5 bases (A,U,G,C) RNA and DNA match up to make a protein. A to the U and G to the C (the U replaces the T). The DNA strand opens up like a zip and the mRNA (messenger RNA) nucleotides come in and match up with it to make a protein. mRNA strand then leaves the nucleus and goes to a ribosome and moves through it. as it moves through it interacts with a small tRNA with 3 bases at a time which match to the mRNA and the amino acids on the tRNA bond with each other to make a chain of amino acids to form a protein
what is cell division
occurs when one cell gets to the end of its life cycle and needs to make a new copy of itself
what are the 2 types of cell division
mitosis and meiosis
what is mitosis
when the cells copy and seperate. Happens to replace a lost or damaged cells. mitosis happens by the DNA copying itself so there are 2 copies of all the chromosomes (2 copies of the mum and 2 of the dad). the chromosmes are then lined up in the middle of the cell and spindles pull them apart, the cell then splits so that their are 2 identical daughter cells both with copies of the mum and dad DNA strands.
what is meiosis
this only happens in sex cells for reproduction. DNA replication occurs again so that there are 2 maternal and paternal copies of the DNA strand. the chromosomes then pair up in independent assortment and strands of a chromosomes swap some of their DNA code to create a whole new sequence of nucleotides bases. The cell then splits and the spindles pull the chromosomes apart so a maternal and paternal of each chromosome go to different cells. Those 2 cells then split again so there are 4 daughter cells with half the amount of DNA and they are not identical.
what are cells
the basic structural and functional units of living organisms.
what are the 3 main components of the cell
cell membrane, nucleus, cytoplasm
what does rough ER do
makes membrane and extracellular proteins and phospholipids, covered in ribosomes
what does smooth ER do
lipid synthesis, detoxification,
what do peroxisomes do
break down toxic substances within the cell
what is the cytoskeleton
framework and support of cell
what does the cilia do
enhances the surface area and can move substances along the surface of the cell
what do proteins in the cell membrane do
transport substances, enzyme activity, attachment to the cytoskeleton, membrane junctions, cell-cell recognition, receptors for signal transduction
what makes a protein
a chain on amino acids
what is interphase
a phase where cells grow, produce proteins and prepare for cell division by replicating DNA
the steps of mitosis
prophase, metaphase, anaphase, telophase
what contains deoxyribose sugar
DNA
what contains ribose sugar
RNA
what happens during prophase phase of mitosis
the chromosomes condense and become visible. the cytoskeleton disassembles as the spindle forms. chromosomes attach to the microtubules and move towards the equator of the cell
what happens during metaphase
the chromosomes are aligned at the equator called the metaphase plate
what happens during anaphase
when the proteins that hold the chromatids together disappear and are pulled to opposite poles
what happens during telophase
a cleavage furrow forms in the center of the cell.
what happens during cytokinesis
the cells seperate into newly formed daughter cells
two stages of meiosis
crossing over and independent assortment
