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Bio - mod. 5
| Question | Answer |
|---|---|
| Scientific name of a sex cell | Gamete |
| Two names referring to a female gamete | Ovum & egg |
| The name used to refer to a male gamete | Sperm |
| Are gametes haploid or diploid cells? | Haploid cells |
| What percentage of the total number of chromosomes are present in haploid cells? | 50% |
| What percentage of the total number of chromosomes are present in diploid cells? | 100% |
| Human diploid cells have 46 chromosomes. How many chromosomes are in human sperm? | 23 chromosomes |
| How many chromosomes are in human ovum (egg)? | 23 chromosomes |
| How many chromosomes are present in a fertilised egg? | 46 chromosomes |
| Are fertilised ova (eggs) haploid or diploid cells? | Diploid |
| Name the type of cell division that create haploid gametes | Meiosis |
| What is internal fertilisation? (with two examples) | When ova (eggs) and sperm are combined inside the female body. E.g. humans and chickens. |
| What is external fertilisation? (with two examples) | When ova (eggs) and sperm are combined outside the female body. E.g. salmon and trout. |
| What is a zygote? | A fertilised egg |
| Type of mammal that lay eggs | Marsupials |
| Type of mammal that give birth to young | Placental mammals and monotremes |
| Two primary roles of the placenta | Allows nutrients and oxygen to be supplied, and wastes to be removed via the mothers blood. |
| Which type of mammal gives birth to the most developed young? | Placental mammals |
| Why are the offspring from marsupials born so small? | As they are not full developed |
| What is the role of a marsupials pouch? | To allow the offspring to fully develop |
| What type of fertilisation occurs in all mammals? | Internal fertilisation. |
| What is the ovarian hormone that thickens the uterine lining? | Oestrogen |
| How is oestrogen produced? | By the follicle during the follicular phase |
| What is the purpose of progesterone? | To stabilise the uterine lining |
| How is progesterone produced? | By the corpus luteum during the luteal phase |
| When does menstruation occur in the ovarian cycle? | From days 1 to 7 |
| What produces GnRH? | The hypothalamus in the brain |
| What gland does GnRH trigger? | The anterior pituitary gland |
| What two hormones are released by th anterior pituitary gland? | Follicle stimulating hormone (FSH) and luterinising hormone (LH) |
| What hormone stimulates follicles to grow in the ovaries? | FSH |
| How does the zygote grow after fertilisation? | Through cell division (mitosis) |
| How long does it take for the embryo to reach the nucleus? | About one week |
| Which cells in the blastocyst go on to form the embryo? | The inner cell mass |
| Which cells in the blastocyst help to form the placenta? | The trophoblast cells |
| Where does the blastocyst implant? | The lining of the endometrium (uterus) |
| What hormone is produced by the blastocyst? | Human chorionic gonadtropin (HDC) |
| Production of the hormone HCG is essential for the embryo to survive. Explain why. | As without HCG, the corpus luteum breaks down and stops releasing hormones which decreases the levels of oestrogen and progesterone. This triggers the uterus lining to shed as a menstrual flow (a period). |
| Pregnancy tests check for the presence of the hormone HCG in maternal urine or blood. Outline why high levels of the hormone HCG suggests a woman is pregnant. | As HCG is produced by a blastocyst which is a young embryo. Therefore, this is an early stage of pregnancy. |
| What is a hermaphrodite? | A species that has the reproductive system of both a male and a female. E.g. flatworm |
| What is sequential hermaphroditism? | It refers to individuals that can change their sex. E.g. clownfish |
| What does parthenogenesis involve (with example)? | A female gamete (egg) developing into an offspring without being fertilised by a male. E.g. stick insects and bees |
| Which form of parthenogenesis creates offspring that are clones? | Eggs being formed by mitosis |
| How is parthenogenesis an advantage for the continuity of a species? | It allows one parent to reproduce. |
| How many plant species are in the plant kingdom? | Over 300,000 species |
| Identify two plant groups that have vascular tissue and produce seeds. | Gymnosperms and angiosperms |
| Traditional Christmas trees are gymnosperms. Do these trees produce flowers? | No. Angiosperms produce flowers. |
| What is meant by the term 'vascular tissues' in plants? | Xylem and phloem tubes |
| How do some plants reproduce asexually in nature? | Many plant species can reproduce asexually as well as sexually. They reproduce asexually by vegetative propagation. |
| Give two examples of gymnosperms. | Conifers and pine trees |
| What are flowering plants called? | Angiosperms |
| What are the male reproductive parts of a plant? | The stamens |
| What does a stamen consist of? | An anther at the top of a stalk, called the filament |
| What do the anthers produce? | Pollen that contains the male sperm cell of a plant |
| What is an example of a pollinator? | A bee |
| What reproductive structure do gymnosperms have instead of flowers? | A cone |
| How do male and female cones differ from each other? | A male cone grows in the lower branches, where as a female cone grows in the upper branches |
| What does the phrase 'alteration of generations' refer to? | Plants having a life cycle in which the organism has a multicellular haploid (1n) stage and a multicellular diploid (2n) stage. |
| What is a gametophyte? | A multicellular, haploid plant structure that can produce gametes. |
| What is a sporophyte? | A multicellular, diploid plant structure that can produce spores. |
| Name the 7 types of asexual reproduction in a plant. | Binary fission, reproduction in fungi by spores, budding, fragmentation, vegetative propagation of plants in runners, bulbs and stem tubers. |
| What is binary fission? What organisms reproduce via binary fission? | An organism duplicates its genetic material (or DNA) and then divides into two new parts. E.g. bacterium and protozoa. |
| What is the reproduction in fungi of spores? (with example of fungal organism) | Asexual spores, which are produced by one parent only (through mitosis) and are genetically identical to that parent. E.g. ascomycota |
| What is budding? (with example of fungal organism) | A new organism develops from an outgrowth or bud due to cell division at one particular site. E.g. yeast |
| What is fragmentation? | An organism is split into fragments. Each of these fragments develop into matured, fully grown individuals that are identical to their parents. |
| What is vegetative propagation of plants in runners? | A runner, is a stem that runs along the ground. At the nodes, it forms adventitious roots and buds that grow into a new plant. |
| What is vegetative propagation of plants in bulbs? | At the base of a daffodil is its bulb, from which roots extend into the ground. In order to create more daffodils, the bulb splits, forming smaller bulbs called bulblets. |
| What is vegetative propagation of plants in stem tubers? | A result of the tiny scale leaves equipped with buds that grow on its surface. Each of these buds can form a new plant, genetically identical to the parent. |
| Do fungi have eukaryotic cells or prokaryotic cells? Are they unicellular or multicellular? | Eukaryotic cells. Most fungi are multicellular. |
| How do fungi gain nutrition? | hey secrete enzymes that enable them to absorb nutrients from the environment. |
| Give two examples of how fungi can harm humans and can help humans | Some fungi can cause diseases in humans such as athlete's foot and ringworm. Some fungi are food for humans (such as mushrooms) & some fungi are used by humans to obtain antibiotics (such as penicillin) |
| What cell structure is found in the cells of plants and fungi, but not in animal cells? | A cell wall |
| What are hyphae? | Multicellular fungi usually grow as tine, branching filaments called hyphae that spread through the material on which the fungus feeds (soil) |
| How can spores of fungi get onto household food to germinate and start growing? | Fungal spores are very light and easily dispersed by breezes into the kitchen where they can colonise on foods. |
| What name is given to unicellular species of fungi? | Yeasts, although most fungi are multicellular |
| How do most unicellular fungi reproduce? | Asexually (with most yeasts reproducing by the process of budding) |
| What happens to the DNA of a yeast before the nucleus divides? | The DNA inside the nucleus replicates |
| What is cytokinesis? | The separation of the cytoplasm to form two separate cells. |
| What is the process by which prokaryotic organisms reproduce? | Binary fission |
| What are the two prokaryotic domains of life? | Bacteria and archaea |
| In binary fission, what happens to the chromosome before cytokinesis occurs? | The chromosome is duplicated |
| What is the difference between the genotype and the phenotype of an organism? | A genotype is the genetic make-up of a particular organism and is internal, where as a phenotype is external and is the appearance, traits and characteristics of a specific organism. |
| Why would growing a plant from a cutting produce a clone? | The cells in the cutting have the same genetic material as the original plant and will grow by mitosis to form a clone of the original plant |
| When grafting is done, which part of the plant is a clone – the scion or the root stock? | The scion is the clone, as it will form the majority of the grafted plant and importantly has the ability to reproduce. |
| Why are plants produced by plant tissue culturing considered clones? | They have only one source of DNA – the parent plant whose tissue was scraped. So, their DNA will be genetically identical to this plant. |
| What is the genetic material of an organism? | DNA |
| How many strands does a DNA molecule usually have? | Two strands |
| What shape is a DNA molecule? | Double-helix |
| Name the sugar in DNA | Deoxyribose |
| What do bases bond to: a sugar or a phosphate? | A sugar. The sugars are bigger than the phosphates. They make up the DNA backbone. |
| After mitosis, how similar is the genetic material in the two daughter cells? | Identical |
| What is the mid-point of a chromosome called? | The centromere |
| How many chromatids can chromosomes be made of? | Two chromosomes |
| What are the four stages in mitosis? | Prophase, anaphase, metaphase and telophase |
| Why is mitosis very important during embryonic development? | Embryos are growing rapidly and need mitosis in order to produce the cells needed for this growth. |
| Identify parts of your body that would have mitosis occur more frequently | Skin cells (for replacement, and for repair of cuts and abrasions. |
| Is cell replication by mitosis important for the continuity of a species? | Yes. In asexual reproduction, offspring are created using mitosis. In all multicellular species, offspring need mitosis for growth and repair in order to survive, so that they can reproduce. |
| How many homologous pairs of chromosomes does a human body cell have? | 23 pairs. The human body has 46 chromosomes in total. |
| Which human cells are haploid? | Ovum and sperm |
| By what process are haploid cells created? | Cell division by meiosis. |
| What is an allele? | A variant of a gene for a particular trait, e.g. the gene for human ear lobe attachment has two variants: attached or unattached. |
| What does 'crossing over' refer to? | Where homologous chromosomes exchange some genetic material (during meiosis). |
| Examples of prokaryotic organisms | Bacteria, archaea |
| Examples of eukaryotic organisms | Animals, plants |
| What are the seven types of proteins? | Signalling, motor, defensive, enzymes, transport, storage and sensory proteins. |
| What contains the instructions for making each type of polypeptide? | Genes |
| What sub-units are joined together to make a polypeptide? | Ribosomes joined to amino acids. |
| Describe the role of tRNA in translation. | tRNA carries triplets of bases called anticodons, as well as a corresponding amino acid. The tRNA anticodons bind to the complementary base pairs in the mRNA codon. |
| Asses the importance of tRNA to the formation of proteins. | The anticodon in tRNA is essential for bringing the correct amino acid to the complementary codon in the mRNA. This ensures that correct amino acid sequences are in the polypeptide chain for the protein being formed. |
| What three mutations can base substitutions cause? | Silent, missense and nonsense. |
| Diagram of protein synthesis | DNA - mRNA - polypeptide - protein transcription translation processing |
| What is a codon? | A triplet of bases in the mRNA that corresponds to an amino acid. |
| ********What is a base substitution? | Base substitutions involve one base being replaced with an incorrect base in a DNA sequence. |
| What negative impact can the sickle cell allele have on humans? | It results in sickle shaped red blood cells and hence poor oxygen transport. |
| What are two ways chromosomes can have numerical abnormalities occur? | When an individual has an extra chromosome or is missing a copy of a chromosomes. |
| What is a mutation? | A mutation is any change to the DNA of an organism that is random and unpredictable. |
| What is it said to be if a person has two identical alleles (with example). | It is said to be homozygous. E.g. FF or ff. |
| What is it said to be if a person has two different alleles (with example). | It is said to be heterozygous. E.g. Ff. |
| What are alternate forms of the same gene called? | Alleles. |
| Are pure breeding plants homozygous or heterozygous? | Homozygous. |
| Are hybrid plants homozygous or heterozygous? | Heterozygous. |
| What is a phenotype? | A phenotype is the appearance of an organism. E.g. a rabbit with brown fur. |
| What is a genotype? | Genotype is determined by the makeup of alleles. E.g. Tt or ff or RR. |
| What chromosomes are in a female? | A female has a homologous pair of X chromosomes (XX). |
| What chromosomes are in a male? | A male has one X chromosomes and one Y chromosome (XY). |
| What term refers to a trait controlled by multiple genes? | A polygenic trait. |
| What is a point mutation? | A mutation involving a single nucleotide (base). |
| What is a structural chromosomal mutation? | A mutation that affects large regions of a chromosome, often involving many genes. |
| What is a chromosomal number mutation? | A mutation in which a cell contains extra or missing chromosomes. |
| What is a germline mutation? | Mutations that occur in a gamete (sperm or egg) or in the cells that divide to give rise to gametes. |
| What is a somatic mutation | Mutations that happen in any cell, other than the reproductive cells. This includes skin cells, muscle cells, lung cells, nerve cells etc. |
| What is biotechnology? | The use of living organisms or their products to create new ways to improve human health and the environment. |
| What is genetic drift? | Genetic drift involves changes in allele frequency in the gene pool of a population due to random chance. For example, CCGCC is the most common and CCCCC is the least common. changes to CCCCC being the most common and CCGCC being the least common. |
| What is a herbicide? | A substance that can kill plants. |
Created by:
T Greenfield
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