Reproduction and Inheritance Flashcards
What are the main features of asexual reproduction?
Asexual reproduction needs only one parent. Since there is only one parent, there is no fusion of gametes and no mixing of genetic information. As a result, the offspring are genetically identical to the parent and to each other. They are clones.
What are the main features of sexual reproduction?
Two different sexes take part in the process.
Testis in male produces the male gametes or sperms and the ovary in female produces female gametes or ova. Sperms and ova come into contact with each other and fuse to form a zygote or egg by a process called fertilisation.
It involves slow multiplication.
How are plants adapted for fertilisation?
Fury stigma, pollen grains
Insect pollination
Large, brightly coloured petals, often sweetly scented, usually contain nectar, moderate quantity of pollen - less wastage than with wind pollination, pollen often sticky or spiky - to stick to insects, anthers firm and inside flower - to brush against insects, stigma inside the flower - so that the insect brushes against it, stigma has sticky coating - pollen sticks to it
Wind pollination
Small petals, often brown or dull green - no need to attract insects, no scent, no nectar, pollen produced in great quantities - because most does not reach another flower, pollen very light and smooth - so it can be blown in the wind and stops it clumping together, anthers loosely attached and dangle out - to release pollen into the wind, stigma hangs outside the flower - to catch the drifting pollen, stigma feathery or net like - to catch the drifting pollen
Conditions needed for germination
Moisture
Oxygen. All green plants need oxygen to “breathe” or respire
Warmth
Female reproductive system
Ovaries- produce eggs
Oviducts- carry the eggs to the uterus, is the site of fertilisation
Uterus- develops the fertilised egg on the placenta
Cervix- entrance to uterus
Male reproductive system
Testis- produce sperm cells, they are stored in the epididymus
The prostate- adds fluid to the sperm, creating semen (as does the seminal vesicles)
The urethra carries sperm to the end of, and out of the penis.
Theroleoftheplacentainthenutritionof
the developingembryo
The embryo can’t breath, digest or excrete.
Blood vessels inside the placenta can absorb the digested food molecules and oxygen that the embryo needs to survive. Waste products will be taken out of the embryo and put back into the mothers blood stream for her to excrete.
Howis thedevelopingembryoprotectedby
amniotic fluid
The fluid (mainly water) cannot be compressed- it absorbs pressure- so any force on the uterus wall will not harm the embryo.
Fertilisation
Is the fusion of the male and female gametes
Pollination
The process in which pollen from one flower is transferred to another flower, before fertilisation can take place.
Vaccinations
When a small dead part of the pathogen is injected into the body to enable the white blood cells to make memory cells in order to be able to make the right antibodies
What is amniotic fluid?
The fluid surrounding developing fetus in the uterus, which protects the foetus from mechanical damage.
What is the anther?
The male part of a flower that produces pollen
What is asexual reproduction?
The production of new individuals without fertilisation, from division of body cells in the parent.
What is the carpel?
The female structure in flowers which contains one or more ovaries and their stigmas and styles.
What is a cutting?
A part taken from a plant and treated so that it grows into a new plant, a form of artificial asexual reproduction of plants.
What is an embryo?
A developing young organism, where cell division and differentiation are taking place rapidly. In plants it develops in the seed. In humans, the embryo is the stage between zygote and fetus.
What is a fetus?
The name given to the developing baby in the uterus
What is fruit?
The soft, fleshy structure surrounding a seed, formed from the ovary after fertilisation.
What is a gamete?
A sex cell
What is the ovary?
A structure that contains immature egg cells
What is the placenta?
The structure formed by a fetus that attaches to the uterus wall and exchanges essential substances between the mother’s blood and the blood of the fetus.
What is an ovule?
The female structure in flower that contains one egg cell
What is a pollen grain?
A male structure in plants that contains the male gamete
What is a pollen tube?
A tube that develops from pollen grain down through the style, carrying the male gamete to the female gamete
What is a seed?
A hard shelled structure formed from an ovule that contains the plant embryo and food stores
What is sexual reproduction?
The production of new individuals by the fusion of a male and female gamete
What is a sperm?
Th male gamete in humans
What is the stamen?
The male structure in flowers that contains the anther
What is the stigma?
The female structure in flowers where pollen grains attach in pollination
What is a style?
A structure that supports the stigma in a flower
What are the testes?
The site of sperm production in men
What is a zygote?
Fertilised egg, formed from the fusion of a male gamete and female gamete
What is an allele?
One form of a gene, producing one form of the characteristic that the gene produces
What is antibiotic resistance?
Resistance to the effect of an antibiotic bacteria, which normally kills them.
What is a base?
One of four molecules (adenine (A), thymine (T), cytosine (C) and guanine (G)) that join in pairs (A with T, C with G) that link the two strands within DNA.
What is a chromosome?
A long DNA molecule that is found in a cell nucleus
What is a clone?
An individual that is genetically identical to other individuals. Codominance is when both alleles for a gene are expressed in the phenotype. A daughter cell is a cell produced by division of a parent cell.
What is diploid?
Diploid describes a cell that contains two sets of chromosomes
What is DNA?
The chemical that forms chromosomes and carries the genetic code
What is double helix?
Double helix describes the shape of the DNA molecule, rather like a twisted ladder
What is a family pedigree?
A diagram that shows the inheritance of different forms of a characteristic through the generations within a family.
What is the genetic code?
The code formed by the order of the bases in DNA that instructs cells how characteristics should be produced
What is a genetic diagram?
A diagram that displays how a characteristic may be inherited by offspring from their parents’ alleles
What is haploid?
Haploid describes a cell that contains only one set of chromosomes, such as gametes.
What is heterozygous?
Where two alleles for a gene are different in the genotype
What is homozygous?
Where two alleles for a gene are the same in the genotype
What is ionising radiation?
Radiation, such as gamma rays, x-rays and ultraviolet radiation, that can damage cells and produce mutations in genes.
What is meiosis?
The form of cell division that produces four haploid, and genetically different, cells from a diploid parent cell, producing gametes.
What is mitosis?
The form of cell division that produces two identical diploid daughter cells from a diploid body cell, used for growth and repair in the body and in asexual reproduction.
What is a monohybrid cross?
Refers to the inheritance of a characteristic produced by one gene.
What is a mutagen?
A chemical that produces mutations in genes
What is a mutation?
A random change in a gene, producing a new allele.
What is natural selection?
The influence of the environment on survival and/or reproduction, so that organisms with some characteristics are more successful at producing offspring than others.
What is phenotype?
The visible characteristics of an organism as a result of its genes. A Punnet square is a form of genetic diagram.
What is a Punnet square?
A form of genetic diagram
What are sex chromosomes?
Chromosomes that affect the sex of the individual, such as, in humans, XX in women and XY in men.
