Flashcards
Reproduction and inheritance
Cards in this deck (34)
- 1How is genetic material stored?Genetic material is contained in the nucleus of a cell in the form of chromosomes. Each cell contains 46 chromosomes, Human body cells are diploid, meaning they store two copies of each chromosome (as pairs).
- 2What is DNA?DNA is a long list of instructions on how to put an organism together and make it work. All of an organism's DNA makes up its genome.
- 3What is a gene?A gene is a section of DNA that codes for one protein.
- 4What is an allele?An allele is a different version of the same gene, which gives different versions of a characteristics (like brown or blue eyes). An allele can be dominant or recessive, a capital letter for a dominant allele and a lowercase letter for a recessive allele.
- 5What is mitosis used for?1) Asexual reproduction (plants and bacteria)
2) Growth
3) Repair - 6What is mitosis?a cell reproduces itself by splitting to form two cells containing identical sets of chromosomes. They are genetically identical.
- 7Describe the process of mitosis,1) The cell gets the signal to divide, causing the DNA to form X-shaped chromosomes. Each arm of the chromosome is identical to the other.
2) The chromosomes line up at the centre of the cell and are pulled apart by cell fibres. The two arms of each chromosome are pulled to opposite ends of the cell.
3) Membranes form around the chromosomes which eventually become the nuclei of the new cells.
4) The cytoplasm divides. - 8What is fertilisation?The process in which a male gamete fuses with a female gamete to form a zygote. The zygote then undergoes cell division and develops into an embryo.
- 9What is sexual production?Sexual production involves the fusion of male and female gametes. because there are two parents, the offspring contains a mixture of their parents' genes (which produces genetic variation in the offspring).
- 10Describe meiosis.Div 1: The cell duplicates its DNA so there's enough for a new cell. One arm of each X-shaped chromosome is a copy of the other.
The chromosomes line up in pairs at the centre of the cell. Each pair contains one chromosome from the mother and one from the father.
The pairs are pulled apart; some of the father's chromosomes and some of the mother's chromosomes go into each new cell - each cell has a mixture of the mother and father's chromosomes, which creates genetic variation.
Div 2: the chromosomes line up in the centre of the cell and the arms of the chromosomes are pulled apart, creating 4 haploid gametes that have a single set of chromosomes and are genetically different. - 11Name the parts of the male reproductive system and describe their functions.1) Glands - produce the liquid added to sperm to make semen.
2) Vas deferens (sperm duct) - a muscular tube that carries sperm from the testis towards the urethra.
3) Urethra - a tube that carries sperm through the penis during ejaculation (urine also exists the body through it).
4) Erectile tissue - swells when filled with blood to make the penis erect.
5) Testis - where sperm are made.
6) Scrotal sac (scrotum) - hangs behind the penis and contains the testes. - 12Name the parts of the female reproductive system and describe their functions.1) Ovary - the organ that produces ova and sex hormones.
2) Fallopian tube (oviduct) - strong muscular tube that carries the ovum from the ovary to the uterus.
3) Uterus (womb) - the organ where an embryo grows.
4) Endometrium (lining of uterus) - has a good blood supply for implantation of an embryo.
5) Cervix - neck of the uterus.
6) Vagina - where sperm are deposited. - 13List the female secondary sexual characteristics.1) Widening of the hips.
2) Development of breasts.
3) Extra hair on underarms and pubic area.
4) Start of period. - 14List the male secondary sexual characteristics.1) Extra hair on face and body.
2) Deepening of voice.
3) Penis and testicles enlarge.
4) Sperm production.
5) Muscle development. - 15Describe the stages of the menstrual cycle.Stage 1: Day 1: menstruation starts; the uterus lining breaks down for about 4 days.
Stage 2: Day 4 to 14 - the uterus lining builds up again into a thick, spongy layer full of blood vessels, ready to receive a fertilised egg.
Stage 3: Day 14 - ovulation occurs; an egg develops and is released from the ovary.
Stage 4: Day 14 to 28 - the wall is maintained. If no fertilised egg has landed on the uterus wall by day 28, the lining breaks down and the cycle starts again. - 16What are the hormones that control the menstrual cycle?1) Oestrogen - produced in the ovaries
- causes the lining of the uterus to grow
- stimulates the release of LH (which causes the release of an egg).
2) Progesterone - produced in the ovaries by the remains of the follicle after ovulation.
- maintains the lining of the uterus during the second half of the cycle. When the level of progesterone falls, the lining breaks down.
- inhibits the growth of LH and FSH. - 17How is the embryo provided with nutrients?The placenta provides the fetus with nutrients. It lets the blood of the fetus and the mother get very close to allow the exchange of food (glucose, amino acids, fatty acids, water, mineral ions and vitamins), oxygen and absorbs waste (carbon dioxide and urea) by diffusion.
- 18What is used to protect the developing embryo?The amniotic fluid within the amnion membrane protects the embryo against knocks and bumps.
- 19What is a genotype and what is a phenotype?A genotype is the combination of alleles that a person has that codes for a particular gene.
A phenotype is the characteristic expressed by the combination of alleles. - 20Define homozygous and heterozygous.If you're homozygous for a trait, you have two alleles the same for that particular gene, e.g. cc or CC.
If you're heterozygous for a trait, you have two different alleles for that particular gene, e.g. Cc. - 21What is inheritance?Passing down characteristics from one generation to the next in genes.
- 22Where is the egg released and fertilised?The egg is released in the ovaries.
The egg is fertilised in the fallopian tube. - 23Name the male reproductive part of a plant and describe its parts.Stamen.
Consists of:
1) Anther: contains pollen grains which produce male gametes.
2) Filament: supports the anther. - 24Name the female reproductive part of a plant and describe its parts.Carpel.
Consists of:
1) Ovary: contains the female gametes inside ovules.
2) Stigma: where pollen grains attach.
3) Style: supports the stigma. - 25How are plants adapted for insect pollination?1) Brightly coloured petals to attract insects.
2) Scented flowers and nectaries.
3) Big sticky pollen grains that stick to insects as they move from plant to plant.
4) Sticky stigma so that any pollen picked up by insects from other plants will stick to the stigma
5) Shorter filament.
6) Shorter style. - 26How are plants adapted for wind pollination?1) Small dull petals on the flower as they don't attract insects.
2) No scents or nectaries.
3) Lots of pollen grains that are small and light so that they are easily carried by the wind.
4) Long filaments that hang the anther outside the flower so that the pollen gets blown away by the wind.
5) Large feathery stigma to catch pollen as it's carried past by the wind. - 27Describe fertilisation in plants.A pollen grain lands on the stigma of a flower.
A pollen tube grows out of the pollen grain and down through the style to the ovary and into the ovule.
A nucleus from the male gamete moves down the tube to join with the female gamete in the ovule.
Feritilisation occurs when the two nuclei fuse together to make a zygote that divides by mitosis to form an embryo.
Each fertilised female gamete forms a seed. The ovary develops into a fruit around the seed. - 28Explain how antibiotic resistance can increase in a population of bacteria.A bacterium can develop a random mutation in its DNA, which may mean that it is less affected by a particular antibiotic. This means that it is better able to survive in a host who is being treated with that antibiotic and so it lives for longer and is able to reproduce many more times. This leads to allele resistance being passed on to lots of offspring and it becomes more common in the population over time.
- 29What is a mutation?A mutation is a rare random change in an organism's DNA that can be inherited.
- 30What is the theory of evolution?Life began as one simple organism from which more complex organisms evolved.
- 31What is variation and what factors affect it?Variation is the physical or behavioural differences in different organisms of a species.
It is affected by genes (eye colour, blood group, inherited disorders) and environment (health, intelligence, sporting ability). - 32Explain natural selection.Darwin concluded that the organisms with the most suitable characteristics for the environment would be more successful competitors and so would have a higher chance of survival and produce more offspring (so a larger part of that population will possess the favoured, 'naturally selected' feature).
- 33What are the four stages of natural selection??1) Variation.
2) Competition.
3) Survival of the fittest.
4) Passing down beneficial alleles to offspring. - 34What do you need to include in your answer when talking about natural selection?1) Variation.
2) Mutation.
3) Survive and reproduce more.
4) Passing on the allele/gene.
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- 11 Biology Flashcards on Reproduction and inheritance, created by m r on 06/12/2022.
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- m r · Dec 2022
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- May 6, 2023
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