Cell Biology - B1

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1 What are prokaryotes?
smaller simpler cells such as bacteria
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2 What are eukaryotes?
complex cells such as animal and plant cells
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3 What is the name for the different parts of a cell?
Subcellular structures
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4 What are the different parts of an animal cell?
nucleus,cytoplasm,cell membrane,mitochondria and ribosomes
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5 What is the function of the nucleus?
contains genetic material that controls the activities of the cell
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6 Cytoplasm
gel-like substance where most of the chemical reactions happen.It contains enzymes that control these chemical reactions
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7 Mitochondria
where most of the reactions for aerobic respiration take plac. Respiration transfers energy that the cell needs to work
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8 Ribosomes
where te proteins are made in the cell
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9 What extra parts does a plant cell have?
rigid cell wall,permanent vacuole,chloroplasts
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10 rigid cell wall
made of cellulose and supports and strengthens the cell
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11 permanent vacuole
contains celll sap a weak solution of sugar and salts
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12 chloroplasts
where photosynthesis occurs which makes food for the plant.They contain a green substance called chlorphyll which absorbs the light needed for photoynthesis
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13 What does a bacteria cell have instead of a nucleus?
single circular strand of DNA that floats frelly in the cytoplasm
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14 What do bacteria not have?
chloroplasts and mitochondria
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15 What is the job of a light microscope?
Uses light and lenses to form an image of a specimen and magnify it.They let us see individual cells and large subcellular strcutures like nuclei
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16 what is the job of an electron microscope?
Use electrons instead of light to form an image,they have a higher resolution meaning they give a sharper image.They let us see things in more detail like the internal structure of a mitochondria and even tiny things
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17 What is the formula for magnification?
magnification=image size/real size
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18 Microscopy required practical
add a drop of water to a clean slide,cut an onion and separate it out into layers,use tweezers to peel off some epidermal tissue,place this into the water on the slide,add a drop of iodine solution to stain so that it highlights objects in a cell,
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19 Microscopy required practical
place a cover slip ontop of it and do this carefully as any air bubbles will obstruct your view of the specimen,use a light microscope to look at your slide and then record your results by drawing and labelling the important features to scale
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20 What is cell differentiation?
The process by which the cell changes to become specialised for its job
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21 What are undifferntiated cells also known as?
stem cells
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22 What are sperm cells specialised for?
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23 what is the function of a sperm cell?
to get the male DNA to the female DNA. It has a long tail and streamlined head to help it swim to the egg.There are alot of mitochondria in the cell to provide the energy released
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24 What are nerve cells specialised for?
rapid signalling
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25 What are the functions of a nerve cell?
to carry electrical signals from one part of the body to another.These cells are really long (to cover more distance) and have branched connections at their ends to connect to other nerve cells and form a network throughout the body
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26 what are muscle cells specialise for?
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27 What are the functions of a muscle cell?
to contract quickly,these cells are long (so they have space to contract) and contain lots of mitochondria to generate the energy needed for contraction
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28 what are root hair cells specialised for?
absorbing water and minerals
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29 what are the functions of root hair cells?
cells on the surface of plant roots which grow into long 'hairs' that stick out into the soil.This gives the plant a big surface area for absorbing water and mineral ions from the soil
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30 What are phloem and xylem cells specilaised for?
transporting substances
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31 What are the functions of phloem and xylem?
they are 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 few subcellular structures so thatstuffcanflow
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32 What are chromosomes and what do they contain?
Chromosomes are coiled up lengths of DNA molecules in the nucleus of the cell
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33 What is the stage of the cell cycle called when the cell divides?
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34 What do multicellular organisms use mitosis for?
to grow or replace cells that have been damaged
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35 - cell cycle - growth and DNA replication
DNA is spread out into long strings,before it divides the cell has to grow and increase the amount of subcellular structures such as mitochondria and ribosomes. It then duplicates its DNA so theres one copy for each new cell.
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36 - cell cycle - growth and DNA replication
The DNA is copied and forms x shaped chromosomes.Each 'arm' of the chromosome is an exact duplicate of the other
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37 - cell cycle - mitosis
Once the cells contents and DNA have been copied it is then ready for mitosis.The chromosomes line up at the centre of the cell and cell fibres pull them apart.The two arms of each chromosome go to opposite ends of the cell.
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38 - cell cycle - mitosis
Membranes form around each of the sets of chromosomes .These become the nuclei of the wo new cells - the nucleus has divided. Lastly the cytoplasm and cell membrane divide.The cell has now produced 2 daughter cells that contain exactly the same DNA
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39 What can undifferentiated cells do?
They can divide to produce lots more undifferentiated cells whcih can differentiate into different types of cell depending on what instrcutions they are given
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40 Where can stem cells be found?
In embryos and adult stem cells
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41 How are adult stem cells already used in medicine?
they cure disease as for example stem cells transferred from the bone marrow of a healthy person can replace faulty blood cells in the patient who recieves them
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42 How are embryonic stem cells used in medicine?
They could be used to replace faulty cells in sick people - you could make insulin-producing cells for people with diabetes ,nerve cells for people with spinal injuries etc
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43 What is therapeutic cloning?
when an embryo could be made to have the same genetic information as the patient meaning that the stem cells produced would contain the same genes meaning they wont be rejected by the patients body
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44 what are the risks of using stem cells in medicine?
stem cells grown in a lab may become contaminated with a virus which could be passed on to the patient and make them sicker
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45 for embryonic stem cells
curing existing patients is more important than the rights of embryos,they are usually unwanted ones which would probably just be destroyed and its allowed in the Uk s long as you follow the strict guidelines
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46 against embryonic stem cells
human embryos shouldnt be used for experiments since each one is a potential human life,campaigners want the right to use embryos banned as well as saying that scientists should find other ways
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47 What is diffusion?
the spreading out of particles from a higher concentration to a lower concentration
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48 What types of things can diffuse?
solutions and gases - perfume,oxygen,glucose,amino acids and water
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49 What is osmosis?
movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
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50 What is a partially permeable membrane?
Just a small membrane with small holes in it so only small tiny molescules can pass througn it and bigger molecules such as sucrose cant
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51 What is active transport?
when substances need to be absorbed against a concentration gradient froma lower to a higher conc gradient
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52 Active transport - root hair cells
Allows the plant to absorb minerals from a very dilute solution against a concentration gradient .But active transport needs ENERGY ffrom respiration to make it work
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53 Active trasnport - in humans
when taking glucose from the gut.Active trasnport allows the nutrients to be taken into the blood desppite the concentration gradient being the wrong way
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54 What can cells use diffusion for?
they can use diffusion to take in substances they need and get rid of waste products
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55 What is transferred during gas exchange between cells and the environment?
oxygen and carbon dioxide
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56 In humans what diffuses from cells into the blood plasma?
Urea (waste prodct produced from the breakdown of proteins) for removal from the body by the kidneys
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57 How are exchange surfaces adapted?
thin membrane so substances only have a short distance to diffuse. They have a large surface area so lots of substances can diffuse at once.In animals they have lots of blood vessels to get stuff in and out of the blood quickly and gas exchange surfa
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58 Exchanging substances - Gas Exchange
Happens in the lung.Lungs job is to trasnfer oxygen to the blood to remove co2 from it .To do this the lungs contain millions of little air sacs (alveoli) where gas exchange takes place
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59 Exchanging substances - how are the alveoli specialised?
Enormous surface area (75m2 in humans).A moist lining for dissolving gases.Very thin walls. And a good blood supply
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60 Exchanging substances - villi
villi provide a really really big surface area.The inside of the small intestine is covered in millions of these little projections called villi.they increase the surface area in a big way so that digested food is absorbed more quickly in the blood
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61 What are villis specialims?
single layer of surface cells and a very good blood supply to assist quick absorption
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62 How does the structure of a leaf let gases diffuse in and out of the cells?
The exchange surface has stomata which the CO2 diffuse through.Oxygen and water vapour diffuse out.The size of the stomata depends on the guard cells .Flattened shape increases the area of exchange surface,
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walls of cells form another exchange surface .the air spaces in these increase the area of this surface so theres more chance of CO2 to get into the cells
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Card 2


2 What are eukaryotes?


complex cells such as animal and plant cells

Card 3


3 What is the name for the different parts of a cell?


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Card 4


4 What are the different parts of an animal cell?


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Card 5


5 What is the function of the nucleus?


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