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135 Cards in this Set
- Front
- Back
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What are the key organelles common to both animal and plant cells and their functions? |
Nucleus - stores genetic information and controls the activity of the cell
Cytoplasm - where most chemical reactions take place
Mitochondria - the site of respiration, where energy is released
Ribosomes - where protein synthesis takes place |
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What are the key organelles found only in plant cells and what are their functions? |
Cellulose cell wall - strengthens the cell
Chloroplast - contains chlorophyll and absorbs light energy to make food Permanent Vacuole - contains cell sap |
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Why do ribosomes rely on mitochondria to function? |
Mitochondria carry out respiration So release energy This energy is needed so the ribosomes can make proteins |
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What are the key features of a bacterial cell? |
Cytoplasm Cell wall Genes are not in a nucleus |
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What are the key features of yeast cells? |
Single celled organisms
Nucleus
Cytoplasm
Cell membrane Cell wall |
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What are the specialised cells? |
Cells that carry out a particular function |
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What is diffusion? |
The movement of particles from an area of high concentration to an area of low concentration |
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Why is oxygen required to diffuse into cells? |
Needed for respiration |
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What is a tissue? |
A group of cells with similar structure and function |
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State three names of tissues and what they do? |
Muscular - contract to bring about movement
Glandular - produces substances such as enzymes and hormones
Epithelial - covers some parts of the body |
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What are the organs? |
Organs are made of different tissues working together |
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Put these in size order: |
Cell (smallest) Tissues Organ Organ system Organism (largest) |
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Give an example of an organ system and how it works |
Digestive system, which includes: Pancreas and salivary gland - which produce digestive juices Stomach and small intestine - where digestion occurs The liver - which produces bile The small intestine - where the absorption of soluble food occurs The large intestine - where water is absorbed from undigested food, producing faeces |
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Name three plant organs |
Stems Roots Leaves |
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State and give functions of the tissues found in leaves |
Epidermal - covers the plant Mesophyll - carries out photosynthesis Xylem - called water around the plant Phloem - carries food around the plant |
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What is the word equation for photosynthesis? |
Carbon dioxide + water -> glucose + oxygen |
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Where is the chlorophyll found? |
Chloroplasts |
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In which part of the leaf is light absorbed? |
Chlorophyll |
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What are the limiting factors for a photosynthesis? |
Carbon dioxide concentration Light intensity Temperature |
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Which gas is released during photosynthesis? |
Oxygen |
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What is light energy used for photosynthesis? |
To convert carbon dioxide and water into glucose |
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Why would leaf not produce oxygen during the night/in the dark? |
No light available So no photosynthesis |
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Why would a leaf take in oxygen during the dark? |
Oxygen is needed For respiration |
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As temperature increases the date of photosynthesis increases, explain why? |
Increase in kinetic energy Increase number collisions Increases rate of reaction |
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If the light intensity increases the date of photosynthesis increases, until a certain level, then even if the light increases there is no further increase in the rate of photosynthesis (remains constant), explain why? |
Light is no longer a limiting factor Another factor is now limiting, e.g. CO2 or temp |
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What are the benefits of growing crops in a green house? |
Increases the yield Controls rate of photosynthesis Increases growth |
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Which factors could a farmer change/control to increase the ratw of? |
Photosynthesis Light Carbon dioxide concentration Temperature Temperature |
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What is glucose used for in plants? |
To produce starch Respiration To produce fat or oil for storage To produce cellulose,, which strengthens the cell wall To produce protein proteins |
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What do plants use from the soil to produce proteins? |
Nitrate ions |
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Why do plants convert glucose to starch? |
Storage |
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When using a lamp to investigate the effect of light on the rate of photosynthesis, what could students to make sure that the heat from the lamp did not affect the results? |
Use a water bath Heat screen LED Low energy light bulb |
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Why would plants growing in higher light levels/receiving more sunlight, grow bigger or produce more flowers? |
More photosynthesis More glucose produced More energy for growth |
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What is the function of the palisade cells? |
Photosynthesis |
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What is the function of the xylem and phloem? |
Xylem transports water and minerals Phloem transports food |
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What is the function of the epidermal cells? |
Cover the plant |
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The distribution of animals may be affected by which factors? |
Availability of food Water Temperature |
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The distribution of plants may be affected by which factors? |
CO2 Water Temperature Light intensity Nutrients |
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The distribution of microorganisms may be affected by which factors? |
Temp Oxygen Nutrients |
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How can you get qualitative date on the distribution of organisms in the environment? |
Random sampling with quadrats Sampling along with a transect |
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When looking at the difference in then number of species between 2 areas which sampling method should we use? |
Quadrats |
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What is a quadrat? |
A frame used as a sample area when measuring distribution and population numbers of organisms (plants and animals) |
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How can you use a transect? |
Transects are not random A tape is stretched between two points. The organisms are sampled along that line at regular intervals using a quadrat. |
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What is the mean? |
The sum of the values divided by the number of the values |
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What is the median? |
The middle value of the range |
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What is the mode? |
The most frequently occurring value |
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What proteins made of? |
Long chains of amino acids Long chains are folded to produce specific shapes |
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List four things that proteins act as: |
Structural components of tissues such as muscles Hormones Antibodies Catalysts |
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What are catalysts? |
Increase the rate of chemical reaction |
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What are biological catalysts called? |
Enzymes (made of proteins) |
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List two factors that could change the shape of an enzyme: |
High temperature High/low pH |
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What is the role of digestive enzymes? |
To break down large molecules into smaller, soluble molecules |
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Name three digestive enzymes : |
Amylase Protease Lipids |
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State where each of these enzymes are made: - Amylase - Protease - Lipase |
Salivary glands Pancreas Small intestine (Amylase) Stomach Pancreas Small intestine (Protease) Pancreas Small intestine (Lipase) |
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What do these enzymes break down? |
Amylase - starch Protease - protein Lipase - lipids |
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What products are made to the enzymes? |
Glucose (Amylase) Amino Acids (Protease) Fatty Acids and Glycerol (Lipase) |
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What acid does the stomach produce? |
Hydrochloric Acid |
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Why does the stomach have acidic conditions? |
The enzymes in the stomach work best in these acid conditions |
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What is bile? |
A yellowish-alkaline liquid Made in the liver Stored in the gall bladder Then released into the small intestine |
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What does bile do? |
Neutralises the acid coming from the stomach Provides alkaline conditions in the small intestine So the enzymes in the small intestine can work at their best |
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How else can enzymes be made? |
Some microorganisms make enzymes |
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How can enzymes be useful in the home? |
Biological detergents contain proteases and lipases to break down stains Biological detergents are more effective at low temperatures (use less energy, therefore cheaper) |
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How can enzymes can be useful in industry? |
Proteases used to 'pre-digest' proteins in baby food Carbohydrases are used to convert starches into sugary syrup Isomerase converts glucose to fructose (much sweeter) and so less is needed - used in slimming foods |
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What are the advantages of using enzymes in industry? |
Carry out reactions at normal temperatures/pressures, so lower costs and energy usage |
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What are the disadvantages of using enzymes in industry? |
Denatured at high temperatures Most are expensive to produce |
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What controls the chemical reactions inside cells? |
Enzymes |
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During aerobic respiration what is used? |
Glucose Oxygen |
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During aerobic respiration what is released? |
Energy
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Where does aerobic respiration take place continuously? |
Plants Animals |
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Where do most of the aerobic respiration reactions take place? |
Mitochondria |
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What is the word equation for aerobic respiration? |
Glucose + Oxygen ----> Carbon Dioxide + Water |
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Name two types of cellular respiration. |
Aerobic Anaerobic |
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Energy is released during respiration. Name four ways in which an organism uses this energy |
To build larger molecules from smaller ones In animals, to enable muscles to contract In mammals and birds, to maintain a steady body temperature In plants, to build sugars, nitrates and other nutrients into amino acids are then built into proteins |
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What happens during exercise? |
The heart rate increases The rate and depth of breathing increases |
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Glucose is stored in muscles, in what form? |
Glycogen |
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During exercise blood flow to the muscles increases, as a result of this there are three further increases? |
Sugar to the muscles Oxygen to the muscles Rate of removal of carbon dioxide |
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If there is insufficient oxygen reaching the muscles what type of respiration takes place? |
Anaerobic respiration |
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During anaerobic respiration, what is incompletely broken down? |
Glucose |
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During anaerobic respiration, what is produced? |
Lactic acid |
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Which produces the most energy: aerobic or anaerobic respiration? |
Aerobic respiration |
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What is required to oxidise lactic acid to carbon dioxide and water? |
Oxygen |
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If muscles are subjected to long periods of vigorous activity they become fatigued. Name one cause of muscle fatigue. |
Build up of lactic acid in the muscles |
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How is the lactic acid removed from the muscles? |
Blood flowing through the muscles |
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Where do most of the reactions of aerobic respiration happen? |
Mitochondria |
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Energy is obtained from aerobic respiration and anaerobic respiration during exercise. Give four differences between aerobic and anaerobic respiration. |
Oxygen is used in aerobic respiration More energy is created from aerobic respiration Carbon dioxide and water are the end products of aerobic respiration Lactic acid is the end product of anaerobic. |
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Name the cell division body cells divide by? |
Mitosis |
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What are chromosomes? |
They contain the genetic information. They are made up of large molecules of DNA |
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What is the structure of DNA? |
The DNA has a double helical structure |
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What is a genetic code? |
A section of three bases on the DNA that codes for an amino acid |
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What are alleles? |
Different forms of the gene is called allele |
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What is a recessive allele? |
An allele that controls the development of a characteristic only if the dominant allele is not present |
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What is a dominant allele? |
An allele that controls the development of a characteristic when it is present on only one chromosome |
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Describe the two stages of mitosis |
Copies of the genetic material are made Then the cell divides once to form two genetically indentical body cells |
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When does mitosis occur? |
During growth To produce replacement cells |
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How many sets of chromosomes do body cells have? |
Two sets of chromosomes (23 pairs) |
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How many sets of chromosomes do sex cells have |
One set of chromosomes |
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What are gametes? |
Sex cell |
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Name the gametes. |
Egg cells in female Sperm cells in male |
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What type of division happens in asexual respiration? |
Mitosis |
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What are stem cells? |
Unspecialised cells that can differentiate to form many different types of specialised body cells. |
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Where do you find stem cells? |
Developing embryo Bone marrow |
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What is differentiation? |
The process by which cells become specialised |
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How does differentiation differ between plant and animal cells? |
Plant cells - it occurs throughout its life and can be changed or revered Animals cells - occurs during embryo development and is permanent |
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What is mitosis? |
Cell division that takes place in normal body cells and produces cells containing the exactly the same genes as their parents. |
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Name the type of cell division that produces gametes. |
Meiosis |
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Describe the process of meiosis |
Copies of the genetic material are made Then the cells divides twice to form four gametes, each with a single set of chromosomes |
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What are the female gametes made? |
Ovaries |
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Where are sperm made? |
In the testes |
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Why is sexual reproduction important? |
It gives to rise to variety |
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What is fertilisation? |
The process where two sex cells join to form a single cell with a full set of chromosomes |
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Explain how sexual reproduction results in variety. |
When the gametes are formed, each gamete has a different combination of chromosomes and there is some exchange of genes When these gametes join together during fertilisation, the combination of chromosomes and mix of alleles results in variation |
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What are the advantages of using stem cells in research? |
They can be used to make any type of adult to repair or replace damaged tissues |
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What are the difficulties with stem cell research? |
Ethical objections Concerns over possible side-effect |
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How can we overcome the ethical issues using stem cells? |
By using stem cells from umbilical cord By using stem cells and therapeutic cloning |
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Why is there an ethical concern over using embryonic stem cells? |
Some people think it is wrong to use potential human being as a source of cells to help other people |
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What was Gregor Mendel known for? |
He was the first person to suggest separately inherited factors |
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What is DNA fingerprinting? |
A method that uses the unique pattern of an individual's DNA to identify the individual |
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What is the human female sex chromosomes? |
XX |
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What is the human male sex chromosomes? |
XY |
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What are homozygous alleles? |
An individual with two identical alleles for a characteristic e.g. DD or dd |
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What are heterozygous alleles? |
An individual with different alleles for a characteristic E.g. Dd |
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What is genotype? |
The genetic makeup of an individual regarding a particular characteristics |
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What is phenotype? |
The physical appearances of an individual regarding particular characteristic e.g. dimples/no dimples |
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What is polydactyly? |
A condition where the individual has extra fingers or toes Is caused by a dominant allele of a gene It needs to be passed onto the offspring by just one parent |
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What is cystic fibrosis? |
Is a disorder of cell membranes, affects mainly the lungs and pancreas Is caused by a recessive allele It needs to be passed on by both the parents |
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Name two symptoms of cystic fibrosis. |
Organs become clogged up with thick, sticky mucus, which stops them from working properly The reproductive system is also affected, resulting in the person with cystic fibrosis to be infertile |
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What are fossils? |
Fossils are remains of organisms from many years ago, which are found in rocks. |
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State the ways by which the fossils are formed |
From the hard part of animals that do not decay easily From parts of organisms that have not decayed because one or more of the conditions needed for decay were absent When parts of the organisms are replaced by other materials as they decay As preserved traces of organisms e.g. footprints, burrows and rootlet traces. |
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Why do we not have any evidence from the early forms of life? |
Many early forms of life were soft-bodied, which means that they have left few traces The few traces that was the left, have been destroyed by geological activity |
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Which is the most common type of fossil? |
Fossils where the harder part of living organism are replaced by minerals over a long period of time |
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When did scientists think that life on earth began? |
Between 3 and 4 billion years ago |
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Describe the process of fossil formation |
An animal dies and falls to the ground The flesh rots, leaving the skeleton to be covered in sand or soil before it is damaged Protected over millions of years the skeleton becomes mineralised and turns to rock. The rocks shift in the earth with the fossils trapped inside Eventually, the fossil emerges as the rocks move and erosion takes place. |
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Give reasons for a species to become extinct |
New predators Environmental change New disease New competitors A single catastrophic event |
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What can we learn from fossils? |
We can learn how much or how little organisms have changed as life has developed on Earth |
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What is mass extinction? |
We can learn how much or how little organisms have changed as life has developed on Earth |
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How can a new species arise? |
Isolation - two population of a species become separated, e.g. geographically Genetic variation - each population has a wide range of alleles that control their characteristics Natural selection - in each population. the alleles that control the characteristic which help the organisms to survive are selected Speciation - the populations become so different that successful interbreeding is no longer possible |
