repro in plants and homeostasis
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| 🇬🇧 | 🇬🇧 |
| What is an incomplete flower? | A flower that lacks any part of a flower (stamens, pistils, petals, or sepals) |
| What is an inflorescence? | Group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches |
| What is pollination? | The transfer of pollen from anther to a stigma to allow fertilization. |
| 2 types of pollination (concerning who the parents are) | Self vs cross pollination |
| Adaptations of self-pollinating flowers | Flowers are contained with anther and stigmas maturing at the same time stigma situated directly below anthers (certain cases) flowers never open |
| Adaptations of cross-pollinating flowers | Dioecious flowers anthers and stigmas maturing at different times stigmas and anthers are situated far away from each other (same flower or plant) or in a way that self-fertilisation is unlikely |
| Dioicious vs monoicious vs bisexual (hermaphrodite) vs perfect | Dioecious - male and female flowers on different plants monoecious - male and female flowers (different flowers) on the same plant bisexual - male and female parts on same flower perfect - same as above |
| Does self fertilization lead to identical offspring, is it the same as asexual reproduction? | No since due to Mendelian inheritance, all alleles of a gene are equally likely to make it into the offspring's gene, resulting in different possible combinations of those alleles. no as there is fusion of gametes |
| Pollination and fertilization process | Generative nucleus undergoes mitosis to form two male gametes pollen settles on a mature stigma stigma secretes a sugary fluid pollen grain breaks, germinates and produces a pollen tube tube cell nucleus directs the pollen tube to grow downwards towards the ovule enzymes are secreted to digest the stigma and style pollen tube goes down the style into the ovary, enters the ovule through the micropyle pollen tubes tip absorbs the sap and bursts, releasing the two male gametes |
| Double fertilisation? | Male gamete fuses with nucleus of the ovum to form a zygote (fertilisation) male gamete fuses with the two polar nuclei to form a triploid cell that will develop into endosperm in fruit later (double fertilsation) |
| Double fertilisation prevent plant from wasting energy how | Both fertilisations carried out at one go it ensures that a plant does not invest energy in forming an endosperm for an ovule that has not been fertilised |
| Post fertilisation events | Ovule > seed zygote > embryo (radicle (root), plumule (shoot),cotyledon) endosperm nucleus > endosperm (present in some seeds, food store is absorbed) ovule stalk > seed stalk ovary > fruit ovary wall > fruit wall (pericarp) stamens and petals wither and fall off sepals may persist and modify to help fruit dispersal |
| Flower parts | Pistil /carpel - female part (gynoecium) contains the stigma, style, ovary, and ovules stamen - male part (androecium) contains the anther and filament petals - corolla sepals - calyx |
| Structure and functionflower | Anther contains pollen sacs which make and release pollen and also contain vascular bundles filament - a stalk that supports the anther and position them in a suitable position for dispersal of pollen grains style - similar to filament except for stigma receiving pollen stigma - sticky/feathery swollen structure that receive pollen grains during pollination ovary - where fertilisation occurs, contains ovules that develop into seeds after fertilisation, develops into fruit after fertilisation integuments - protective layers around the ovule sepals - modified green leave that protect the flower bud and petals petals - modified leaves big and brightly colored for insect pollinated |
| Structure and function2flower | Receptacle - enlarged end of flower stalk which contains the other parts of the flower pedicel/flower stalk holds the flower in place (proper position) |
| Two types of pollinators | Wind and insect |
| How useful are flowers to the pollinators | Provide food (pollen contains amino acids and nectar contains carbohydrates) |
| How do bees help pollination in bisexual flowers | They help deposit pollen grains on the stigma by brushing their hairs on the anther, collecting them, and brushing against the sticky stigma which sticks the grains to it, allowing tube generation and fertilisation |
| 3 types of cells in an ovule | Antipodal, egg cell (zygote later), and polar nuclei (triploid cell after) |
| Fertilization? | Fusion of gametes (sperm + egg cell) which forms the embryo and later the plant fusion of male gamete with two polar nuclei to form triploid cell which becomes endosperm |
| Endosperm function? | Food and nutrients for embryo |
| Convection, radiation, conduction and evaporation | In evaporation, heat is lost as latent heat of vaporisation (evaporation of water from body surfaces or breathing passages cooling the body) radiation: electromagnetic waves exchange usually infrared convection: transfer of heat via moving currents taking heat away (wind over a hot body) conduction: direct transfer of heat via contact |
| Why is thermoregulation needed during exercise? | Maintenance of heat loss and gain, maintaining a normal body temperature to prevent heat stroke, etc. |
| What produces heat in active muscles? | Respiration, cellular respiration, metabolism, aerobic respiration, anaerobic respiration. breaking down glucose into lactic acid and energy, releasing heat in the process during anaerobic |
| How does heat released in the muscles travel to other part of the body | Heat released by cellular respiration and also by the working of the muscles are carried by blood vessels near the skin of the body,where it is lost to the environment. when blood flows in the blood vessels that surround muscle tissues, the blood gains heat by conduction and warms up as the blood flows in the blood vessels that surround the other body organs, it loses heat by conducting heat away to the bodily organs. |
| Same body temp at different times of the day? why yes/no | No because it depends on the time of day and the activities we are involved in |
| Core vs skin temp | Core is higher |
| Why body temp needs to be within a certain range | Chemical reactions like digestion can occur at a fast enuf rate these reactions require enzymatic action to speed up enzymes work best at optimum temp. too high and enzyme denaturation occurs, changing the structure of the active sites and causing enzymes to work less efficiently |
| Fuwwy OwO weduce heat loss? | Fur and adipose tissues (like blubber) trap air or provide a coating of poor conductor of heat, which retains heat from the body thus reducing heat loss via convection and conduction (not radiation as em waves can pass easily thru most things) temperature at different depths of the body (fur,skin,fat,muscle) is different |
| Internal vs external environment | Internal environment- cytoplasm external environment- interstitial/extracellular fluid |
| How does the external environment maintain a stable internal one | Nutrients from the external diffuse in while metabolic wastes go out |
| What is homeostasis | A process that maintains a relatively stable internal environment of the organism, regardless of changes in the external environment. requires chemical energy from food. stable can be of temperature in the case of thermorgulation |
| Other than temperature, what else can be regulated | Solute potential |
| Thermoregulation | Internal body temp within a tolerable range controlling heat gain and heat loss mechanisms in the body gain heat? anabolism and catabolism (respiration and such) (physiological mechanism) from the sun and intake of hot food and beverage lose heat? evaporation of sweat and expired air (physiological mechanism) from exposed surfaces via conduction, convection andor radiation excretion |
| Thermoregulation feedback mechnism | Receives signals from thermoreceptors compares with the setpoint decides on appropriate response sends signals to effectors effectors (eg. muscles) produce response to change the controlled condition |
| Positive feedback | Response enhances original stimulus |
| Skin layers | Epidermis (with malpighian layer), dermis, and subcutaneous |
| Two structures involved in temperature regulation | Thermoreceptors and skin arterioles |
| Structure and function thermoregulation and skin | Just check the photo |
| Hair erector muscles | Increase in temp > erector muscle relax > hair lies flat (opposite for decrease in temp) when increase in temp, the air circulate over the skin better, removing heat via convection and conduction decrease in temp, traps air which is a poor conductor of heat, reducing heat loss via conduction and convection doesnt have much effect on humans |
| Blood vessels controlling heat gain/loss | High temperature - skin arteriole vaso-dilate while shunt vessels vaso-contract, diverting blood to the capillaries, bringing warm blood near the surface of skin so heat is more easily lost via convection, conduction, radiation, and the evaporation of sweat as latent heat of vaporisation, increasing heat loss low temperature - skin arteriole vaso-constrict while shunt vessels vaso-dilate, diverting blood away from the capillaries, bringing warm blood further away the surface of skin so heat is less easily lost via convection, conduction, radiation, and the evaporation of sweat as latent heat of vaporisation, reducing heat loss |
| Sweating and metabolic rate | As temperature increases, active sweat glands produce more sweat due to more blood near the skin, increasing heat loss when water evaporates,the vapour taking away heat in the form of latent heat of vaporisation metabolic rate drops to produce less heat (opposite for decrease in temp) |