Instant Notes: Plant Biology

Section I – Plants, water and mineral nutrients I4 Uptake of mineral nutrients by plants Nutrientsare taken up as ions dissolved ...

uptake into cells and into the root can be regulated. This means that roots accu- mulate some ions against a concentration gradi ...

The endodermis Theendodermisdevelops near the point of development of the root vascular tissue (Topic C2). Cells of the endoderm ...

Section I – Plants, water and mineral nutrients I5 Functions of mineral nutrients A nutrient is essentialif: (i) it is required ...

(negative) or a cation(positive). The distinction between macro- and micro- nutrients is to some extent arbitrary as some specie ...

Nitrogen Nitrogen gas is abundant in the aerial and soil environment, but unlike oxygen cannot be used directly. Nitrogen is fix ...

Phosphate Phosphateis not reduced in the plant. Root cells contain phosphate trans- portersat the plasma membrane and after upta ...

Section J – Metabolism J1 Photosynthetic pigments and the nature of light The energy for photosynthesisis derived from sunlight, ...

ring structure, with a magnesium atomat its center, and a tail of hydrocarbons, which anchors the molecule to a membrane. Chloro ...

J1 – Photosynthetic pigments and the nature of light 137 CH 2 CH N N N N Mg CH 3 CH 3 A CH^2 CH^3 CH^3 CH 3 C O O OCH 3 O CH C C ...

Section J – Metabolism J2 Major reactions of photosynthesis In photosystem II (PS-II) (Topic J1) a pair of electrons energized b ...

electrons are replaced by a unique process called photolysisin which water is oxidized to yield molecular oxygen. The overall re ...

produces NADPH and a proton gradient across the thylakoid membrane. NADPH is used directly in the Calvin cycle(below). The proto ...

The Calvin cycle TheCalvin cycle has three stages: carboxylation, the incorporation of CO 2 ; reduction, utilizing ATP and NADPH ...

consume further ATP or NADPH. The pathway involves the activity of seven enzymes in total. Finally, ribulose 5-phosphate (5C) is ...

photorespiratory cyclewhich are located in peroxisomes (Topic B1) and mito- chondria (Topic B3). The stages are shown in Fig. 5. ...

Section J – Metabolism J3 C3 and C4 plants and CAM Land plants have a dilemma: allowing a free diffusion of CO 2 into leaf cells ...

apparatus of many plants showing C3 photosynthesis, the type of photosyn- thesis described in Topic H2 (so called because its fi ...

malate; malate is then stored in the vacuole (Fig. 2). In the light, malate is released from the vacuole and broken down to yiel ...

Table 1. Examples of C4 and CAM plants Family Common examples C4 plants Amaranthaceae Amaranths Asteraceae Asters and daisies Eu ...