Are Eyewitness Identifications Reliable?

Are Eyewitness Identifications Reliable? Eyewitness identifications during identification procedures such as show ups, live line ups and photo line ups are reliable to an extent in the forensic discipline, but are mostly fallible when assisting police with their enquiries regarding suspects and offenders, due to the fact that the reliability is dependent on a variety of factors relating to the memory of the witness and situational context of the crime. There are three types of memories: sensory memory, (â€Å"very short duration for which sense-based information is held post exposure† (Lecture (2015)), short – term memory (â€Å"information that can be stored for approximately thirty second without rehearsal† (Lecture (2015)) and long-term memory (â€Å"the unlimited amount of information that can be stored over a lifetime of rehearsal† (Lecture (2015)). The computer memory model refers to the factors relating to the input of information, the passage of time for which the information is stored an d output of eyewitness information through different types of questioning. The input aspect of the computer memory model can be separated into witness and situation categories which include factors such as stress and age. Stress is a crucial factor when determining the reliability of eyewitness identification as it can diminish the accuracy of the memory and is largely dependent on whether the victim or witness has experienced a violent crime such as an armed robbery or aggravated assault. Research studies have been conducted in the area of stress/arousal, concluding that there is a correlation between high anxiety exposure and errors associated with eyewitness memory. Coinciding with this research finding is the correlation between trait anxiety and a significantly lower frequency in errors associated with eyewitness memory. A research study was conducted by the University of London, investigating the effects of high state anxiety on the participant’s abilities to identify and describe the antagonist from a horror labyrinth present in a line up. This was sparked due to the fact that 215 individuals were acquitted after being falsely imprisoned in the United State of America following the re-opening of cases using DNA from the crime scenes(Valentine and Mesout, (2009), page 151). This â€Å"mistaken eyewitness identification was a cause of the miscarriage of justice, of 75% of these cases† (Valentine and Mesout, (2009), page 151). The study consisted of two sample groups; the first sample group consisted of 20 employees from a retail store whose participation helped legitimize the state anxiety inventory. Each employee’s standard heart rate was monitored and recorded during a brisk seven minute walk prior to entering the labyrinth, once entered the participants encountered a frighteni ng individual before continuing on with the exhibit and completing the state anxiety inventory questionnaire forty five minutes later. This sample proved that there was an increase in heart rate which was caused by psychological arousal when entering the London Dungeon. The eyewitness study group consisted of 56 participants and also encountered the scary person in the labyrinth; similarly they completed the state anxiety questionnaire forty five minutes later and a trait anxiety questionnaire followed by a â€Å"written free call description of the scary person† and a â€Å"cue recall† before rating their confidence after completing an impartial photo line-up consisting of nine individuals. The results of the research study concluded that â€Å"participants who reported lower state anxiety recalled more correct descriptors† (Valentine and Mesout, 2009, page 157), which would obviously indicate that â€Å"people who reported higher state anxiety recalled fewer correct details† (Valentine and Mesout,2009, page 157) of the antagonist. Furthermore, â€Å"participants who reported high state anxiety were less likely to correctly identify the [scary person]† (Valentine and Mesout, 2009, page 158), which is statistically shown as â€Å"only 17% of eyewitness[es] correctly identified the person from a nine-person culprit-present photograph line-up† (Valentine and Mesout, 2009, page 159). Additionally, there is a link between sex and state anxiety suggesting that male eyewitnesses are more accurate in their identification in comparison to their female counter-parts, which could be due to the fact the females experienced higher anxiety levels than males in London Dungeon (Valentine and Mesout, 2009, page 158, 159). However, regardless of the different results between sexes and state anxiety, overall the results clearly indicate that psychological arousal experienced during exposure to high stress situations for both genders, si gnificantly affects the ability of eyewitnesses to recall information and recognize culprits during identification procedures, which diminishes their reliability. Similarly, a field study was also conducted during U.S Army survival school training, which was imperative for gaining optimal research results rather than research studies conducted in laboratories. The investigation was conducted on â€Å"five hundred and nine†¦ active –personnel enrolled in military survival school training† (Morgan et al., 2004, page 3). The participants were separated into four different studies, each focusing on a specific identification procedure when attempting to recognize instructors during simulated high and low stress interrogations during the prisoner of war camp phase of training. Of the 228 participants in the first study group which focused on the live line-up method of identification, 188 participants were interrogated by two instructors while 40 participants were interrogated by one instructor (Morgan et al., 2004). The second study group consisted of 114 subjects which focused on the photo line-up method of identification (Morgan et al., 2004). The third group comprised of 167 participants who focused on the photo line-up method while under high stress and lastly the fourth group focused on the photo line-up identification method while under low stress (Morgan et al., 2004). Following the interrogations and according to the identification method their study group focused on, each participant was required to identify the instructors present in the questioning. The results confirmed the general point of view that by exposing individuals to high stress situations, the subject’s ability to recognize the target person was impaired due to the overwhelming influx of emotions the participant experienced at the time. The data collated suggests that the criminal justice system would benefit substantially in reducing the number of cases of innocently imprisoned individuals, if law enforcement agencies shifted their attention towards the sequential method of eyewitness identification. Statistics indicate that th e sequential photo method is considerably accurate than the live line-up and photo –spread method (Morgan et al., 2004). This is due to that fact that study group 3 and 4 scored the lowest in high stress situations; â€Å"49%†(Morgan et al., 2004, page 8) in their ability to â€Å"correctly identified their interrogator† (Morgan et al., 2004, page 7) , â€Å"100%†(Morgan et al., 2004, page 8 ) in their ability to â€Å"correctly identified that their interrogator was not present in the †¦ sequential presentation of photos† (Morgan et al., 2004, page 7), and recorded fewer errors â€Å"(51%)†(Morgan et al., 2004) in their ability to â€Å"not pick their true interrogator â€Å"(Morgan et al., 2004, page 7), in comparison to study group 1 and 2, who were focusing on alternative identification methods. Furthermore, evidence suggests that eyewitness identifications can be increasingly reliable during high stress situations with the aid of cued photographs (49%)(Morgan et al., 2004, page 9) than without (â€Å"66%†)(Morgan et al., 2004, page 9 ). Nevertheless, regardless of different identification procedures, the reliability of eyewitnesses to recall and recognize the target person under high anxiety is steadily lower compared to low anxiety situations. Like stress, the ability of eyewitnesses to correctly identify the target person during procedures of recognition, is dependent on the age of the witness therefore only reliable to an extent. Most research studies conducted conclude with findings indicating that the ability to accurately identify the culprit is higher among teenagers and young adults, in comparison to middle aged and older adults, as the common conception is that with age comes reduced facial recognition due to impaired memory. However, most of these research studies include young assailants therefore failing to recognise that eyewitness identifications of older adults are reliable to an extent, if the trigger person is of the same age. A research study group conducted two experiments in London, experiment 1 consisted of â€Å"113† [random]†¦Caucasian male† (Wright Stroud, 2002, page 645) participants, who were inexperienced in identification procedures and were selected from either their â€Å"workplace leisure area or around the university† (Wright Stroud, 2002, page 645). The subjects were then divided in two sample groups depending on their age, â€Å"between 18 and 25† or†¦ 35 and 55 years old† (Wright Stroud, 2002, page 645). Both sample groups comprised of approximately half young adults and half middle aged adults, and were assigned to either a â€Å"1-day or [a] â€Å"1-week condition† (Wright Stroud, 2002, page 645). Participants were required to independently view four videos for which â€Å"two showed a car being stolen [(by one young culprit in the first video and one adult culprit in the second video)] and two showed a television being stolen [(by one young culprit and one adult culprit)]† (Wright Stroud, 2002, page 645). Volunteers were then required to accurately identify the trigger person in a culprit present photo line-up consisting of â€Å"six fillers and one culprit† (Wright Stroud, 2002, page 645), a day or week later. Results collated indicate that middle aged adults assigned to the one day condition find it notably difficult in identifying young offenders, scoring only 24% in the ability to positively identify the younger culprit (Wright Stroud, 2002). Results continued to decline for middle aged adults assigned to the one week condition as they were only 20% accurate in positively identifying the younger culprit in comparison to younger adults, scoring 47% in their accuracy after one day and 29% after one week (Wright Stroud, 2002). However, results indicate that although middle aged adults struggled to accurately identify the young assailant in the one day condition, their ability to positively identify there same age culprit scored 47% in accuracy. Experiment 2 was conducted similarly, although it explored if age biases were present during culprit absent photo line-ups. The study consisted of an additional â€Å"180† (Wright Stroud, 2002, page 649) subjects which were divided again into two separate age groups ranging from â€Å"18 and 33 or between 40 and 55 years old† (Wright Stroud, 2002, page 649). Researchers also removed the one week condition from the experiment as â€Å"effect size was largest for the 1-day delay† (Wright Stroud, 2002, page 649) in the first experiment. Participants viewed the four crime videos again and were then required to accurately identify the trigger person in a culprit present or culprit absent photo line-up. Among both age groups, the accuracy of subjects increased by 10% when the assailant and filler were of the same age of the participant’s during the culprit present line-up (Wright Stroud, 2002) , which was also evident in first experiment. However, during culprit absent photo line-up, the statistics indicated that â€Å"own age biases† (Wright Stroud, 2002, page 652) exist only with culprit present photo line-ups due to the fact that middle aged adults won’t â€Å"be more likely than younger participants to identify an innocent young suspect, but they will be more likely to fail to identify a guilty young culprit† (Wright Stroud, 2002, page 652). Similarly, a research study was conducted with broader younger and older age groups, ranging from â€Å"16-33 years and †¦ 60- 82 year[s] [old]† (Memon, Bartlett, Rose Gray, 2003, page 44). The study consisted of â€Å"172† (Memon, Bartlett, Rose Gray, 2003, page 44) volunteers for which younger participants were selected from their respective â€Å"local colleges† (Memon, Bartlett, Rose Gray, 2003, page 44) ,while older participants were selected based on their reply to local flyers in â€Å"local centres, clubs, and societies† (Memon, Bartlett, Rose Gray, 2003, page 44). Participants were required to participate in a â€Å"face-source recollection task† (Memon, Bartlett, Rose Gray, 2003, page 45) prior to watching two videos for which there was a young offender or older offender engaging in a criminal activity. Subjects were then â€Å"assigned to the delay or immediate test condition [session]† (Memon, Bartlett, Rose Gray, 2003, page 46) and took part in â€Å"two line-ups with the perpetrator [either] present or †¦.absent† (Memon, Bartlett, Rose Gray, 2003, page 46). They were then subsequently made to repeat the facial recollection task for which participants needed to identify â€Å"old (seen in session 1) or new (not seen in session 1)† (Memon, Bartlett, Rose Gray, 2003, page 46) faces. The median statistics of younger versus older adults indicate the same results as of experiment 1 and 2 of the previous article, that overall, younger participants were able to correctly identify the culprit (â€Å".86†) (Memon, Bartlett, Rose Gray, 2003, page 46) regardless of time delay in comparison to older participants (â€Å".49†) (Memon, Bartlett, Rose Gray, 2003,page 46). However, the most notably important relationship of the statistics, is the correlation between the accurate recognition of culprits among both age groups and the â€Å"measure of source recollection derived from a separate face-recognition task† (Memon, Bartlett, Rose Gray, 2003, page 43). Results reveal that older adults recorded noticeably poorer on the task thus indicating that â€Å"source-recollection deficits are partially responsible for age-related differences in performance of the line-up task† (Memon, Bartlett, Rose Gray, 2003, page 43). Mistaken identification by eyewitnesses during show up, live line-up and photo line-up procedures, contribute significantly to the number of unjustly imprisoned individuals, some of which (340) have already been executed. Almost all research studies conclude with contradictory evidence to one another however there are clear patterns among results of factors, which influence the reliability of eyewitness recall and recognition. The situational factor of witness stress/psychological arousal, determines the extent for which eyewitness recall are dependable on during testimonies. Exposure to high stress situations, increase state anxiety, which diminishes the dependability of eyewitness memory recall across both genders. Variables such as gender differences also indicate that women in comparison to men are less accurate in their ability to identify and describe the trigger person. However, the assistance of cued photographs during sequential photo method identification procedures, have p roven to increase accuracy of descriptors and facial recognition of the perpetrator, which if implemented across the criminal justice system, would increase the reliability of eyewitness identifications along with reducing the number of innocently imprisoned citizens. Strict guidelines for unbiased questioning during eyewitnesses interviews, would also reduce suggestibility and implanted false memories. The most contradictory research evidence stems from the accuracy of younger and older eyewitnesses. Although studies generally show that younger adults are more accurate in either identifying or describing culprits, these studies fail to recognise that to an extent, that younger adults are only higher in their accuracy rates, due to the fact that young culprits are mostly used across all studies. Eyewitness reliability in terms of age was dependant on a variety of factors. Firstly, experiments conducted have shown that there is a correlation between higher accuracy results of older adults and their ability to identify same age (older) culprits in target present line-ups. Secondly, time also played a crucial factor as accuracy of both age groups were dependant on short or long delays in recognition, with older participants decreasing in accuracy with increasing time. However overall, younger participants were slightly more accurate regardless of age difference and time delay. This wou ld indicate that immediate questioning and identification procedures would increase the accuracy of identifications for older eyewitnesses. By Mathew Franczak References Wright, D., Stroud, J. (2002). Age differences in lineup identification accuracy: People are better with their own age. Law And Human Behavior, 26(6), 641-654. doi:10.1023/a:1020981501383 Valentine, T., Mesout, J. (2009). Eyewitness identification under stress in the London Dungeon. Appl. Cognit. Psychol., 23(2), 151. doi:10.1002/acp.1463 Morgan, C., Hazlett, G., Doran, A., Garrett, S., Hoyt, G., Thomas, P. et al. (2004). Accuracy of eyewitness memory for persons encountered during exposure to highly intense stress. International Journal Of Law And Psychiatry, 27(3), 265-279. doi:10.1016/j.ijlp.2004.03.004 Memon, A., Bartlett, J., Rose, R., Gray, C. (2003). The Aging Eyewitness: Effects of Age on Face, Delay, and Source-Memory Ability. The Journals Of Gerontology Series B: Psychological Sciences And Social Sciences, 58(6), P338-P345. doi:10.1093/geronb/58.6.p338 The Mitochondria: Structure, Functions and Reactions The Mitochondria: Structure, Functions and Reactions Mitochondria are rod-shaped structures that are enclosed within two membranes the outer membrane and the inner membrane. The membranes are made up of phospholipids and proteins. The space in between the two membranes is called the inter-membrane space. The structure of the various components of mitochondria are as follows: The outer membrane is a relatively simple phospholipid bilayer, containing protein structures called porins. Ions, nutrient molecules, ATP, ADP, etc. can pass through the outer membrane with ease. The inner membrane is freely permeable only to oxygen, carbon dioxide, and water. Its structure is highly complex, including all of the complexes of the electron transport system, the ATP synthetase complex, and transport proteins. There are folds present which are organized into lamillae (layers), called the cristae. The cristae greatly increase the total surface area of the inner membrane which makes room for many more of the above-named structures than if the inner me mbrane were shaped like the outer membrane. The membranes create two compartments. The intermembrane space is the region between the inner and outer membranes. It has an important role in the primary function of mitochondria, which is oxidative phosphorylation. The matrix is a complex mixture of enzymes that are important for the synthesis of ATP molecules, special mitochondrial ribosomes, tRNAs and the mitochondrial DNA. Besides these, it has oxygen, carbon dioxide and other recyclable intermediates. In glycolysis, what type of reactions do hexokinase and phosphofructokinase catalyze? In general, what is the importance of these reactions or in other words what makes them unique in the glycolysis pathway? The first step in glycolysis is phosphorylation of glucose by a family of enzymes called hexokinases to form glucose 6-phosphate (G6P). This reaction consumes ATP, but it acts to keep the glucose concentration low, promoting continuous transport of glucose into the cell through the plasma membrane transporters. In addition, it blocks the glucose from leaking out because the cell lacks transporters for G6P. Phosphofructokinase (PFK) is a glycolytic enzyme that catalyzes the irreversible transfer of a phosphate from ATP to fructose-6-phosphate. Because this reaction is irreversible, PFK is the key regulatory enzyme for glycolysis. When ATP levels are high in the cell, the cell no longer needs metabolic energy production to occur. In this case, PFKs activity is inhibited by allosteric regulation by ATP itself, closing the valve on the flow of carbohydrates through glycolysis. In general, how are fats and proteins utilized during cellular metabolism? Proteins contain carbon, hydrogen, oxygen, nitrogen , and sometimes other atoms. They form the cellular structural elements, are biochemical catalysts, and are important regulators of gene expression . Digestion breaks protein down to amino acids. If amino acids are in excess of the bodys biological requirements, they are metabolized to glycogen or fat and subsequently used for energy metabolism. If amino acids are to be used for energy their carbon skeletons are converted to acetyl CoA, which enters the Krebs cycle for oxidation, producing ATP. The final products of protein catabolism include carbon dioxide, water, ATP, urea, and ammonia. What two molecules combine in the TCA cycle to form Citrate? Where did each precursor molecule come from? The Citric Acid cycle begins with acetyl-CoA transferring its two-carbon acetyl group to the four-carbon acceptor compound called oxaloacetate to form a six-carbon compound called citrate. Acetly-CoA is created when from the reaction of pyruvate dehydrogenase. Oxaloacetate is created from a combination of pyruvate carboxylase and Malate dehydrogenase. Would you expect to find the pyruvate dehydrogenase complex in an anaerobic bacterium? Explain why or why not and explain what task this complex performs. Pyruvate dehydrogenase complex is a complex of three enzymes that transform pyruvate into acetyl-CoA by a process called pyruvate decarboxylation which involves the oxidation of pyruvate. Since anaerobic bacterium only exists in oxygen-free environments you would not expect them to contain this complex. What are high energy electrons and what is represented by an oxidation-reduction potential? Using this knowledge briefly explain the importance of Figure 5.14 and the role of the high energy electrons carried by NADH and FADH2 in the creation of ATP. Why are the electron transport chain complexes referred to as proton pumps? Electron transport chains are biochemical reactions that produce ATP. ATP is made by an enzyme called ATP synthase. ATP synthase is powered by a transmembrane proton gradient, which conduct protons from high to low concentration across the membrane. In essence working to pump protons through a proton channel which temporarily opens in the inner membrane How are NADH and FADH2 different when it comes to interacting with the ETC? NADH+H+ arrives from Stage II of carbohydrate metabolism or Stage III (TCA cycle) to the ETC and immediately oxidizes to NAD+ with its protons (hydrogen ions) going into the matrix and its electrons (e-) going to cytochrome complex 1. As the electrons arrive on cyctrochrome complex 1 the complex immediately goes through redox (reduction and oxidation). This reaction creates a proton pump within the cytochrome, pumping some protons from the matrix through the cytochrome into the intermembrane space. The electrons now transfer to mobile carrier Q and NAD+ returns to its original source. FADH2 arrives from the TCA cycle to the ETC and goes directly to cytochrome mobile carrier Q. FADH2 oxidizes to FAD with its protons going into the matrix and its electrons going to mobile carrier Q. Mobile carrier Q shuttles the electrons from FADH2 (and from cytochrome 1) to cytochrome complex 2. The electrons are transferred to cytochrome complex 2 and it immediately goes through redox (reduction and oxidation). This creates a proton pump, pumping protons from the matrix through cytochrome complex 2 directly into the intermembrane space of the mitochondrion. FAD returns to the TCA cycle. What does the proton-motive force represent (you dont need to explain the formula)? A proton-motive force represents the energy that is generated by the transfer of protons or electrons across an energy-transducing membrane. Describe the structure of ATP synthase and the binding change hypothesis of mitochondrial ATP production. ATP synthase is made up of two portions, F1 and F0. The FO portion is within the membrane of the mitochnodria and the F1 portion is above the membrane, inside the matrix of the mitochondria. The binding change mechanism involves the active site of a ÃŽÂ ² subunit cycling between three states. In the open state, ADP and phosphate enter the active site. The protein then closes up around the molecules and binds them loosely the loose state. The enzyme then undergoes another change in shape and forces these molecules together, with the active site in the resulting tight state binding the newly-produced ATP molecule with very high affinity. Finally, the active site cycles back to the open state, releasing ATP and binding more ADP and phosphate, ready for the next cycle of ATP production. Describe the structure of a chloroplast and give a brief summary of its evolutionary origin. The chloroplast is the organelle where photosynthesis occurs in photosynthetic eukaryotes. The organelle is surrounded by a double membrane. Inside the inner membrane is a complex mix of enzymes and water. This is called stroma and is important as the site of the dark reactions, more properly called the Calvin cycle. Within in the stroma is a network of stacked sacs. Each stack is called a granum and each of the flattened sacs which make up the granum is called a thylakoid. Each thylakoid has a series of photosystems and associated proteins. The photosystems contain chlorophyll and other pigments and all these associated structures in the thylakoid membrane are the site for the light reactions in which light energy is converted to chemical energy needed for the Calvin cycle in the dark reaction. Chloroplasts are believed to have arisen as free living bacteria that became endosymbiont with the ancestors of photosynthetic eukaryotes. An endosymbiont is any organism that lives within the body or cells of another organism. Briefly describe the experiment performed by Ruben and Kamen and describe what this experiment helped to prove. Ruben and Kamen bombarded graphite in the cyclotron, a type of particle accelerator,in hopes of producing a radioactive isotope of carbon that could be used as a tracer in investigating chemical reactions in photosynthesis. Their experiment resulted in production of carbon-14. What is the photosynthetic role of the light-harvesting antenna pigments? In photosynthetic systems a variable number of pigments act as light-harvesting antenna to absorb and direct solar energy to photochemical reaction centers. The effectiveness of the reaction centers depends on the efficient transfer of excitation energy from these antenna molecules. In plants, what are photosystems, what is the significance of the primary P680 and P700 pigments, and how do these fit into the Z scheme arrangement depicted in Figure 6.10 of your text? Photosystems are protein complexes that are found in the thylakoid membranes of plants. They are involved in photosynthesis as enzymes which use light to reduce molecules. There are two families of photosystems. Within photosystem type 1 is the P700 reaction center. Its absorption spectrum peaks at 700 nm. When photosystem I absorbs light, an electron is excited to a higher energy level in the P700 chlorophyll. These electrons are moved in pairs in an oxidation/reduction process from P700 to electron acceptors. Within photosystem type II is the P680 reaction center. Its absorption spectrum peaks at 680nm. What is photolysis and what is its significance during photosynthesis? Photolysis is defind as the splitting or decomposition of a chemical compound by means of light energy or photons. Photolysis is the part of photosynthesis that occurs in the granum of a chloroplast where light is absorbed by chlorophyll, turned into chemical energy, and used to split apart the oxygen and hydrogen in water. The oxygen is released as a byproduct while the reduced hydrogen acceptor makes its way to the second stage of photosynthesis, the Calvin cycle. What is photophosphorylation and how is this accomplished by PSII and PSI? Photophosphorylation is the production of ATP using the energy of sunlight. In photophosphorylation, light energy is used to create a high-energy electron donor and a lower-energy electron acceptor. Electrons then move spontaneously from donor to acceptor through an electron transport chain. When a special chlorophyll molecule of PSII absorbs a photon, an electron in this molecule attains a higher energy level. Because this state of an electron is very unstable, the electron is transferred from one to another molecule creating a chain of redox reactions, called an electron transport chain (ETC). The electron flow goes from PSII to cytochrome b6f to PSI. In PSI the electron gets the energy from another photon. The final electron acceptor is NADP. Cytochrome b6f and ATP synthase are working together to create ATP. This process is called photophosphorylation What is the function of Rubisco? In the Calvin Cycle of photosynthesis, the enzyme rubisco grabs CO2 and incorporates it into RuBP (commonly called carbon fixation). The cycle continues until one G3P is made; a precursor to glucose. What is the usefulness or function of the the 12 GAP molecules produced by the fixation of 6 CO2 molecules via the Calvin cycle? The function is for the manufacturing of carbohydrates What is the function of phosphoenolpyruvate carboxylase and what advantage is given to plants that contain this enzyme? Phosphoenolpyruvate carboxylase is an enzyme in the family of carboxy-lyases that catalyzes the addition of CO2 to phosphoenolpyruvate (PEP) to form the four-carbon compound oxaloacetate. Carbon fixation via PEP carboxylase assimilates the available CO2 into a four-carbon compound (oxaloacetate, which is further converted to malate) that can be stored or shuttled between plant cells. This allows for a separation of initial CO2 fixation by contact with air and secondary CO2 fixation into sugars by RuBisCO during the light-independent reactions of photosynthesis. In succulent CAM plants adapted for growth in very dry conditions, PEP carboxylase fixes CO2 during the night when the plant opens its stomata to allow for gas exchange. During the day time, the plant closes the stomata to preserve water and releases CO2 inside the leaf from the storage compounds produced during the night. This allows the plants to thrive in dry climates by conducting photosynthesis without losing water through open stomata during the day.